No doubt earnings are lower than casino. Two reasons: It’s an entry market, it is something to get into now to enjoy better revenues in the future.
Also, players do tend to spend less. BUT – if you have patience and the program assigns you the player for life, the players do end up getting more and more skilled, and the better players will generate some decent revenue.
Much like poker.
You also need a good info site so players will send you their friends. Word of mouth advertising is still very important in these new and specialized markets.
This is also the reason why cobranded sites are a good thing for affiliates here, people send their friends to your site.