Problem with esports is the amount of inconsistencies and riggings that take place. Lag, disconnections, cancellations.
There is a good edge in lines though if you know what you're betting on. Seen some nice underdogs hit.
This is becoming more and more rare as eSports become bigger. I follow the CS:GO scene, and there were some riggings earlier this year or last year, and the people who did do the rigging have been banned from pretty well all leagues and tournaments, and it appears they are going to be permanently banned.
Lag and d/c's are also being mitigated, and many websites that offer betting are refunding bets if any of these things happen. And pro teams nearly never has this happen, or it will be known before the game begins.
eSports are going to be a huge thing, I am willing to guarantee it. CS:GO is getting a televised league, "eLeague" by Turner, DoTA 2 has The International which is being televised, and League of Legends is big enough on its own. They will most likely be watch alongside standard sports, and have sites over them to the same extent.