First prize for Titled Tuesday is $1,000. 2nd is $750. Goes a long way in some countries if you're winning that weekly.
But as I wrote in my article, I suspect it happens most for things like speedruns where you're trying to create tons of content in a short amount of time
Pretty much everyone plays online chess with zero stakes, and has no incentive to cheat for small gains. Combined with a potential big loss in reputation, widespread cheating would be illogical - exactly different than baseball and cycling.