I used to play email chess a long time ago, in fact someone on this forum also I met there before I picked up on bitcoin. It is fun, but you always knew when you were playing against someone using computer software, which is impossible to detect just have a lot of suspicion when you try ask them why they make the move and they cannot explain.
Well, that is only one of the downside when playing chess and waging money with someone you just met online because, the security is much more likely to be tampered with using bots or softwares. But, the idea of true players gambling by playing chess is great, does not mostly rely only on luck but also, in each other's skill as a chess player.
Haven't played chess online but, you should check mostly the security features in the site instead on focusing for a possible win.
I would like to try it soon, played chess in school. These kinds of gambling sites is good because it tests not only your luck but mostly your skills.