I think the biggest benefit of playing poker is that you learn to use your skill and power of concentration.
There are a lot of benefits from playing Poker, keeping your mind active is beneficial especially for us older players as it keeps the old grey matter exercised, also there is the benefit of Social interaction between players who would probably not meet in normal daily life, the game teaches us to be patient and disciplined when playing hands, and of course there is the benefit of extra Cash if you can regularly make the money and sometimes win.
I proved to myself that anything is possible if you put your mind to it, I once said to my local Landlord I would go to the next Regional Final in our League game, If I finished 1st and won the trophy, He just replied if I wanted a trophy that bad, He would give me the one behind the bar, to which I replied "That is not the same" "I want to win it, not be given one".
I did it that very season, and again in the following season, I have lost count of the number of times I actually qualified in 2nd or 3rd place, then given up my seat to another player, you have to understand that for me the important part, when playing Poker is not the money, but winning the game, winning the League, or winning the Finals. 2 out of 3 is not bad and the best I ever did in the Finals was finish 2nd so there is room for improvement.
When the fun Stops, STOP!