I have read most of this thread, and it is very interesting question indeed.

My response:

Taken as a hobby in con-langs it has an impressive community (I don’t speak it though). This is to be compared to other con-langs, not other natural languages. Just the number of learners or historical connotation do not make it necessary preferrable to other con-langs in this day and era.

I believe its practical purpose as international lingua franca is defeated by its Eurocentrism and the actual spread and expansion of its users. It is not a matter of merely the number of users but where and how you actually often they meet them.

For this reason I think it is better to follow the advice I read elsewhere (I think on Lemmy), like French and Spanish can open up many more communication opportunity in ex-colonies, and we should really pay more attention to languages or families that have been local lingua franca in localities of Asia and Africa, to have a more global perspective.