[lacerrr]

it's just artificial growth, though. You're not generating any more engagement than if they'd just show you the content as a guest. Unless you also started using the app as a result of creating an account.

[nine_k]

The growth may be artificial and not sustainable, but the money it brings is real, and can be invested (or consumed) sooner than later. Opportunity cost is a real thing :-\

[patmorgan23]

They've covered non-logged in engagement into logged in engagement, which lets them target ads better.

[alluro2]

Or at least immediately fees you presumably more relevant posts from people you follow, so that you can engage more and they can serve more ads.