So you're completely rejecting the potential scenario that this is all some big game and the guy has paid the staged witnesses and everyone to claim your robbed him?
Remember that winning the lottery has such low odds that there can be multiple games in a row where not one of the millions of ticket buyers win, and someone going you a suitcase of cash without it being a trick or a scam has even lower odds of happening then that.
I guess what I'm asking is how likely are you to trust the money in such a scenario, where you don't have omnipotent knowledge of the truth of if the money is for real or if the guy plans to screw you over for multiple times the amount of money in the suitcase.
Maybe the money is real, and the guy lost a bet with his friends or some other scenario that's irrelevant.
Maybe he desperately needed you to complete a simple task for him, one that's fully achievable at the time the money is handed over to you.
Maybe the money is fake or only the top bills are real, and aside from you being pranked there isn't much consequences for you
Maybe a month later it turns out he did something sketchy or framed you as stealing from him and you'll have to pay back every cent, or maybe even more and you end up in jail.
There's just no way to know for certain, but it certainly seems plausible that he's just giving you the money with no demands or restrictions.