Yes, that code will disable the account activation email for all users. It sounds as though that is safe to do for your case.
Here is a simplified version of the code that will disable the account activation email for all users:
add_filter( 'discourse_email_verification', 'wpdc_custom_disable_email_verification' );
function wpdc_custom_disable_email_verification() {
return false;
}
This code needs to be added to either a WordPress plugin, or to your theme’s functions.php file. Adding it to the functions.php file is the easiest way to do it. If you are editing that file on a live site, you should access the site’s file system through its cPanel, save a backup of functions.php and then copy and paste the code into the original file. If everything works as expected, delete the backup file.