This old article explains the reasoning well:
Former Square Enix executive Jacob Navok has shared his thoughts on less-than-expected sales of the latest Final Fantasy games. He also tried to explain why people mistakenly think that the Japanese publisher is simply setting unrealistic goals for its products.
gameworldobserver.com
In short, money hats are recouped. It's not just free money on top of what you earn.
To work through a simplified example:
Sony: Here's 200m for 1 year of playstation exclusitivity
SE: Sure!
(game proceeds to sell 3.33 m copies over a year, earning 200m)
SE: Hurray! With Sony's moneyhat and the new revenue, we now have 400m!
Sony: Actually, I get 200m back. I recoup my investment!
SE: :O
(SE & Sony now both have 200m)
(Game finally launches on Xbox and Steam, but hype and sales are considerably decreased)
Now, picture the other scenario where SE launched on all platforms simultaneously, sold 3.33m on playstation (same as before) PLUS an additional 4m between PC and Xbox. They would have a LOT more money.
Since moneyhats are recouped, you should take it only if you can't fund development yourself or if you think the game would sell less than the money hat (case of Alan Wake 2 on Epic). But if your game will sell gangbusters and will exceed the moneyhat, then there's basically no reason to take it.