Alternate strawman: you do not use paid upgrades and at some point stop making enough money to continue developing and supporting the app and the API. All of your users are screwed , too.

It's easy to envision hypothetical situations and they're all already possible, leaving customers stuck having to gauge how serious a company is and how sustainable their business model will be. Paid upgrades don't change this situation but do offer a currently blocked way for developers to make apps with a long-term plan