Why is reCAPTCHA Essential?

odoo.define('your_module_name.signup_recaptcha', function (require) {
    'use strict';
    const publicWidget = require('web.public.widget');
    const { ReCaptcha } = require('google_recaptcha.ReCaptchaV3');
    publicWidget.registry.SignupCaptcha = publicWidget.Widget.extend({
        selector: ".oe_signup_form",
        events: {
            submit: "_onSubmit",
        },
        tokenName: "signup",
        init() {
            this._super(...arguments);
            this._recaptcha = new ReCaptcha();
        },
        async willStart() {
            return this._recaptcha.loadLibs();
        },
        _onSubmit(ev) {
            if (this._recaptcha._publicKey && !this.$el.find("input[name='recaptcha_token_response']").length) {
                ev.preventDefault();
                this._recaptcha.getToken(this.tokenName).then((tokenCaptcha) => {
                    this.$el.append(
                        `<input name="recaptcha_token_response" type="hidden" value="${tokenCaptcha.token}"/>`
                    );
                    this.$el.submit();
                });
            }
        },
    });
});

odoo.define('your_module_name.signup_inherit', function (require) {
    'use strict';
    var publicWidget = require('web.public.widget');
    var SignUpForm = publicWidget.registry.SignUpForm;
    publicWidget.registry.SignUpForm = SignUpForm.extend({
        _onSubmit: function () {
            var $btn = this.$('.oe_login_buttons > button[type="submit"]');
            if ($btn.prop("disabled")) {
                return;
            }
            $btn.attr('disabled', 'disabled');
            $btn.prepend('<i class="fa fa-refresh fa-spin"/> ');
        },
    });
});

import logging
import requests
from odoo import http, _
from odoo.http import request
from odoo.exceptions import UserError
from odoo.addons.auth_signup.models.res_users import SignupError
from odoo.addons.auth_signup.controllers.main import AuthSignupHome
_logger = logging.getLogger(__name__)
class WebSignup(AuthSignupHome):
    @http.route('/web/signup', type='http', auth='public', website=True, sitemap=False)
    def web_auth_signup(self, *args, **kw):
        qcontext = self.get_auth_signup_qcontext()
        if not qcontext.get('token') and not qcontext.get('signup_enabled'):
            raise werkzeug.exceptions.NotFound()
        if 'error' not in qcontext and request.httprequest.method == 'POST':
            try:
                # C U S T O M  C O D E  S T A R T
                if not request.env['ir.http']._verify_request_recaptcha_token('signup'):
                    raise UserError(_"Suspicious activity detected by Google reCaptcha.")
                # C U S T O M  C O D E  E N D
                self.do_signup(qcontext)
                # Send an account creation confirmation email
                if qcontext.get('token'):
                    User = request.env['res.users']
                    user_sudo = User.sudo().search(
                        User._get_login_domain(qcontext.get('login')), order=User._get_login_order(), limit=1
                    )
                    template = request.env.ref('auth_signup.mail_template_user_signup_account_created', raise_if_not_found=False)
                    if user_sudo and template:
                        template.sudo().send_mail(user_sudo.id, force_send=True)
                return self.web_login(*args, **kw)
            except UserError as e:
                qcontext['error'] = e.args[0]
            except (SignupError, AssertionError) as e:
                if request.env["res.users"].sudo().search([( "login", "=", qcontext.get("login"))]):
                    qcontext["error"] = _( "Another user is already registered using this email address.")
                else:
                    _logger.error("%s", e)
                    qcontext['error'] = _( "Could not create a new account.")
        response = request.render('auth_signup.signup', qcontext)
        response.headers['X-Frame-Options'] = 'DENY'
        return response
    @http.route('/web/reset_password', type='http', auth='public', website=True, sitemap=False)
    def web_auth_reset_password(self, *args, **kw):
        qcontext = self.get_auth_signup_qcontext()
        if not qcontext.get('token') and not qcontext.get('reset_password_enabled'):
            raise werkzeug.exceptions.NotFound()
        if 'error' not in qcontext and request.httprequest.method == 'POST':
            try:
                # C U S T O M  C O D E  S T A R T
                if not request.env['ir.http']._verify_request_recaptcha_token('password_reset'):
                    raise UserError(_"Suspicious activity detected by Google reCaptcha.")
                # C U S T O M  C O D E  E N D
                if qcontext.get('token'):
                    self.do_signup(qcontext)
                    return self.web_login(*args, **kw)
                else:
                    login = qcontext.get('login')
                    assert login, _( "No login provided.")
                    _logger.info(
                        "Password reset attempt for <%s> by user <%s> from %s",
                        login, request.env.user.login, request.httprequest.remote_addr)
                    request.env['res.users'].sudo().reset_password(login)
                    qcontext['message'] = _( "An email has been sent with credentials to reset your password")
            except UserError as e:
                qcontext['error'] = e.args[0]
            except SignupError:
                qcontext['error'] = _( "Could not reset your password")
                _logger.exception('error when resetting password')
            except Exception as e:
                qcontext['error'] = str(e)
        response = request.render('auth_signup.reset_password', qcontext)
        response.headers['X-Frame-Options'] = 'DENY'
        return response