Another benefit of online gambling is that you need not tip any employees. In case of traditional gambling, you will have to tip waiters and dealers for the service.
This all could add up to big amount if you gamble frequently. I am surprised no one else mentioned it before here.
First of all, it is not compulsory to tip the waiter or other staff that provide pleasing services to customers. It is all up to individual whether he feels like tipping anyone or not. The concept of rewarding someone this way is showing ones satisfaction. No one will punish him for not doing so. Secondly, losing money in useless bets is more dangerous than the mentioned point and only this matters really.