Memecoins are pyramid schemes where you're gambling on more suckers coming in behind you to keep the ball rolling while you do a rugpull and get your money out before it collapses.  The reason the valuation is so high is that it's an imaginary number based on multiplying the coin's fully diluted value, the imaginary value it's supposed to vest at, by the number of coins projected to exist when they vest ("become unlocked").

Obviously, you can make that number anything you want.

Not sure how useful it'll be for money laundering because it's designed so everyone else can't get their money out before the rugpull happens.