Choosing the reputable site can at least give you the peace of mind that your personal data will be safe from them and of course you’ll get to experience the best gambling site. Security is a big thing that you must not ignore, if there’s a 2fA option do it, that is for your own benefit and for your own security.
Though sometimes, 2FA is not the indicator if a casino is legitimate or not. There are casinos out there that impose 2FA all the while being a scam in reality. They get two birds in one stone with you submitting your personal info plus giving them some money should you wish to deposit on them. The key is looking for authentic reviews for the site and see if it has established user base already. A rule of thumb I'd like to follow is if there isn't a thread for the casino already existing here in bitcointalk, it could be a possible scam - at least for me.