I think the point is if you charge upfront for storing peoples data under a certain price plan, you're less likely to change anything regarding the deal because you're in the business of storing peoples data. If you do bad, people will stop using the service, and you lose your business. You're more aligned with your users.

Compare it to Google, where they can operate under a loss for a particular service (like Google Photos) in order to increase profits in a different market (like AI recognition tools). Once they are done with whatever they wanted to do, they can close down the service without much consequence, the business lives on.