There will be only two major things in this case
#1 Super fast betting rolls, which you can check on 999dice. Despite the site is a scam site we can see alot of regular players playing there. One of the reason that they are still hanging there would be that 999dice offer a near instant rolling which no other sites offer
#2 Near to zero house edge. In this case it will be Blackjack because it offer the less house edge for the gambling industry , do however having a dice sites that offer less than a standard 1 % house edge will be a good addition though.
P.S : Anyway I found a site which has both of this and that a simple design that ease you to play and load the site whenever you are having a bad connection can be a thing to be considered as well
Indeed it is a way for gambling sites to lure in more player, especially new player in the gambling industry. Most player fell for the deposit bonus and that they had no idea that it will require them to wager it for certain fold before being able to withdraw it and thus they lost it in the wagering process
Actually luckyflop offered a pizza as one of their promotions if you could stay up for 4 hours and play on 1/2 ring games . More info here https://bitcointalksearch.org/topic/its-official-luckyflopeu-only-pokerpizz-night-free-pizza-wednesdays-1063238