It's not that simple! This looks to be the case when you're the center of your own universe, but the effects cascade to everyone around them-- once landlords and merchants realize all these wage slaves now have money to burn, they raise prices of everything to capture as much of that as they can. You can no longer remain solvent as a $2 rice-picker; in order to compete with the prostitutes, you're forced to become one yourself. It's only the illusion of choice; if there were a way to make that much money through other means, you'd be doing it already.
This "hack" only works if you're among the first few people to do it. Once everybody is doing it, supply outpaces demand, and now you have to do something even more degrading to stand out from the others in competing to earn the privilege of sucking off some schlub. It's a race to the bottom...and beyond.
Lack of control for inflation is why UBI won't ever work, and why fraud and prostitution are problems. Much as we can't survive off of eating our own shit, you can't have a sustainable economy or civilized society built on rampant cannibalization.