https://news.ycombinator.com/newsguidelines.html

"Be kind. Don't be snarky. Converse curiously; don't cross-examine. Edit out swipes."

Plenty of banks will freeze your bank account instantly.

And good luck convincing them that you stumbled upon $400k by solving a puzzle - only takes one suspicious fraud/risk manager to conclude that there’s a higher chance of fraud than legitimacy.

(But you are right, no problem to find someone to pay you the market price. That’s a done deal in seconds)