People were laughing at e-sports not long ago, now we have million dollar championships. It wont take long for e-sports to become as big as regular sports like football. The new generations aren't that interested in regular sports and eventually e-sports will surpass regular sports. Unfortunately there aren't that many e-sports championships out there.
I think it's very difficult to bet on an esport. Too little information and too much statistics and results. The rotation of the players is too high and the stability is very low. This has to be developed very much, but it's very difficult.