That sounds like bad design.

If you get hit by a car once, that doesn't mean you want to get hit by a car more times in the future.

What ends up happening with this algorithm is that the "for you" page is dominated by posts asking open-ended questions for engagement. You want to see game clips or screenshots, but every recommended post will ask "What game do you like the most?" or "What character of game X do you like that most?" A question that the author isn't really interested in knowing, asked only to farm engagement from passerby users.

I think that's a really ugly situation all around and a failure of how the system was designed. People should be able to just tell the algorithm what they want to see without secret trackers that promote perverse incentives.

Also, for twitter in particular, buying a subscription is pretty much buying ads on the For You page. Since users can choose to hide the blue checkmark that indicates they are paying for preferential treatment, that means, effectively, that those are promoted posts that aren't marked as "promoted" like normal ads would have to be. I think that's illegal.