The other reason it matters, the number of bookmarks helps tell you how important a post is, alongside likes, read counter, cumulative read time, etc.
We should strengthen bookmark a lot and make it more useful.
The other weakness of “topic timers” is that they are per topic. Why? Why can’t I get reminded of two different posts in the same topic at different times.. or pick the first post if I want a “topic” bookmark reminder. Having this be per post is more logical / flexible and is already how bookmarks work.
I would love bookmark to be improved to be the “remind me about this” feature because it already is, it just never nags you like it should..