Everything in your post seems to give reasons for recreational gambling, and I do agree that the stakes are part of the game, and one with no stakes is markedly different. It does seem though that this is all in service of fair play, and to reward those for requiring they pay to prove they are in good faith.

To me I dont think the potential reward is the point with recreational gambling. You might even give your winnings back in a friendly game were you to find out that the stakes bled out into real life.

However I dont see how all of this applies to gambling as a profession and as a part of society in larger ways such as stock markets and Crypto currency. What's the supposed benefits of that?

I would argue that the professional setting is not recreational at all, and in many cases is abusive, with there seeming to be some intent to disguise how abusive it is to the victim.