One nice thing about SatoshiDICE is that it is easy to externally audit. It grew so fast because it was among the best methods for wagering. There is no way for me to know for sure if the wagers that appear in the chat (troll) box for wallet-based wagering sites are actual wagers or if they've been fabricated to make it look like lots of play is occurring.
BitZino had publicly shared some growth numbers some time ago and they were impressive:
-
https://bitzino.com/about/numbers/10_million_handsBut still even if all the Bitcoin-based online casino sites were doing as well, the aggregate amount is still a tiny fraction of all online wagering, which itself is a tiny fraction of casino gaming that occurs.
But not having the most popular wagering service doesn't mean it isn't either sustainable or useful. But collectively the sites keep getting better (e.g., see
http://BitcoinVideoCasino.com's latest update), providing more value (e.g., the higher payout available with
http://just-dice.com), available in a wider scale (e.g., Bitcoin Video Casino's mobile app for Android), more entertaining (e.g., .... [your suggestions here]), etc.
