Yes the users are quite active. The main thing people are paying for are the video features and the video scraper. There is some code which allows the app to pull videos from youtube, instagram, facebook, twitter, reddit, etc, and I think that is really the thing that separates this app from other generic image editors.
Oh sure, YouTube forbids that. Once there's enough traffic to care, it'll get cut off. But YouTube is somewhat unlikely to try to sue one's socks off for breaking the ToS. Copyright owners though...
Same, but on the other hand memers do seem to take their craft seriously. While I wouldn't want to pay monthly for this app as I would use it a few times a year (I'll just fire up photoshop), I guess its not too much cash for users serious about creating. Apparently you can make some good cash focusing on a niche user market.
Something interesting I found is that the many of the 'power users' of the meme world have many different meme making apps and they pay for most of them!
We’ve long spent resources on increasing attention and popularity; might this expense be similarly justified? Having a meme generator at one’s fingertips seems a timely way to increase standing in the online culture participated in.
Are the users active? Have you thought / analyzed if they pay and forget that it's a subscription? :-?