I remember when Memrise told us that you looked into mem use and found that users weren’t “engaging with them” much. This “research”, though, happened after mobile had already been launched without showing mobile users any mems at all. It happened after the user interface on web (where you could use mems) hid all mems by default, unless you knew to click a subtle link or button of some sort that you could easily never notice unless someone told you about it.
Even users who did use mems knew that by then, mems were kind of a secret that most Memrise users would never come across, so many of us had stopped treating them as the shared platform they used to be, and were mainly creating mems for our personal use. I may have been one of the holdouts, still trying hard to make popular mems that would help other people, but it was a somewhat bitter experience doing so and knowing they would really only help people I personally talked to and showed how to find them.
When I made my courses, making mems for the things in my courses was part of it. I considered those mems part of the course. When mems got more and more hidden, including from all new web users (unless they found the obscure way to enable them in the web UI), that’s one of the things that discouraged working on and expanding courses.
If Memrise ever decides again that being a community platform is worth anything, then among the many other changes you should make, you should throw out that pointless and misleading old research, and support & emphasize mems for real.