Difference between wp_insert_user() and wp_create_user()

There is no difference between wp_insert_user() and wp_create_user(). The entire source of wp_create_user() is given below

function wp_create_user($username, $password, $email = '') {
    $user_login = esc_sql( $username );
    $user_email = esc_sql( $email    );
    $user_pass = $password;

    $userdata = compact('user_login', 'user_email', 'user_pass');
    return wp_insert_user($userdata);
}

It just calls insert version almost immediately, basically a shorthand wrapper.