Some may not require you to identify yourself at the registration point but may ask for that later, and that's the kind of sites that we should be careful of.
I just can't see a reason for using other site then NitrgoenSports,they offer the best odds and also are known for being legit for a long time.
They have been here since 2013 and I can't see them going away any time soon.
Nitrogen Sports is currently number 1 among the crypto-currency sportsbooks, however, in each case there must be competition, which as a result helps all crypto-currency bookmakers become better and better.