It’s not a real fight so he doesn’t take an L on his record. With the heavy favorite he is he could funnel some cash to other people to make huge bets against him on his behalf.
It would set up a huge rematch where Floyd would want it to be a sanctioned fight in Vegas and put up his 0 to make it bigger.
Nothing is off the table here.
The humiliation Floyd would deal with from actually losing is something he'd never want. People criticize his wins and still say he loss. Imagine losing to a YouTuber. Imagine a lucky punch that knocks him out. The memes would be endless.