[angry young man]

Generating income for yourself allows you to circulate the money to people that run restaurants, movie theaters, car dealerships, etc. and in that way contributes to society. Other than economic vageries like that I wouldn't say playing poker contributes anything to society or is a profession to be particularly proud of but I don't think it's doing any harm or anything to be ashamed of either. I certainly don't think it's dishonest to try to be better at a game than someone else and reap the benefits from that.