Kira-kira cara saya ini bener ngga ya?

Cara ini berhasil tapi saya pengen tau mnurut agan2 cara ini ada kelemahannya ngga ya?

JAVASCRIPT

// LOGIN TEMPLATE
Vue.component("login", {
    template: "#login-template",
    methods: {
        login: function () {
            let email = $("#email-login").val();
            let password = $("#pass-login").val();
            let action = $(".submit-btn").data("name");
            let xhr = new XMLHttpRequest();

            xhr.onreadystatechange = function () {
                if (xhr.readyState == 4 && xhr.status == 200) {
                    $("#hasil").html(xhr.responseText);
                }
            }
            xhr.open("GET", `ajax.php?
                            action=${action}&
                            email=${email}&
                            password=${password}`, true);
            xhr.send();
        }
    }
})

// REGISTER TEMPLATE
Vue.component("regis", {
    template: "#regis-template",
    methods: {
        validasi: function () {
            let forms = document.forms[0];
            let lolos = true;
            for (i = 0; i < forms.length - 1; i++) {
                if (forms[i].value.length <= 0) {
                    forms[i].classList.add("err");
                    lolos = false;
                } else {
                    forms[i].classList.remove("err");
                }
            }

            return lolos;
        },
        regis: function () {
            let nama = $("#nama-regis").val();
            let email = $("#email-regis").val();
            let profesi = $("#profesi-regis").val();
            let foto = $("#foto-regis").val();
            let password = $("#pass-regis").val();
            let action = $(".submit-btn").data("name");

            if (this.validasi()) {
                let xhr = new XMLHttpRequest();
                xhr.onreadystatechange = function () {
                    if (xhr.readyState == 4 && xhr.status == 200) {
                        console.log(xhr.responseText)
                        $("#hasil").html(xhr.responseText);
                    }
                }
                xhr.open("GET", `ajax.php?
                                nama=${nama}&
                                email=${email}&
                                profesi=${profesi}&
                                foto=${foto}&
                                action=${action}&
                                password=${password}`, true);
                xhr.send();
            }

        }
    }
})

PHP

<?php

    $conn = mysqli_connect("localhost","root","","trips");

    $nama = $_GET["nama"];
    $email = $_GET["email"];
    $profesi = $_GET["profesi"];
    $foto = $_GET["foto"];
    $password = $_GET["password"];
    $action = $_GET["action"];


    switch($action) {
        case "regis" :
            // REGISTER
            $emailcek = mysqli_query($conn, "SELECT email FROM users WHERE email='$email'");
            if(mysqli_num_rows($emailcek)) {
                echo "<script>alert('Email Sudah Terdaftar')</script>";
            } else {
                $password = password_hash($password, PASSWORD_DEFAULT);
                mysqli_query($conn, "INSERT INTO users VALUES ('','$nama','$email','$profesi','$foto','$password')");
                if(mysqli_affected_rows($conn)) {
                    echo "<script>alert('Berhasil Registrasi')</script>";
                }
            }
        break;

        case "login" :
            $emailcek = mysqli_query($conn, "SELECT * FROM users WHERE email='$email'");
            if(mysqli_num_rows($emailcek)) {
                $passCek = mysqli_fetch_assoc($emailcek);
                if(password_verify($password, $passCek["password"])) {
                    session_start();
                    $_SESSION["nama"] = $passCek["nama"];
                    echo "<script>location.replace('index.php')</script>";
                } else {
                    echo "<script>alert('Password Salah')</script>";
                }
            } else {
                echo "<script>alert('Email dan Password tidak cocok')</script>";
            }
        break;
    }


?>