I would argue that a substantial reason for their popularity is also just that devs have fun when developing them.
With most other genres, you've seen the story a gazillion times, you've done each quest a thousand times etc.. It just gets boring to test the game and it becomes really difficult to gauge whether it still is fun to someone who isn't tired of it.
Meanwhile with roguelikes, the random generation means that each run is fresh and interesting. And if you're not having fun on your trillionth run, that's a real indicator that something needs to be added or improved.


Apparently, Wikifunctions is a place to define e.g. mathematical formulas, so that they can be executed ad-hoc to provide insights about common questions.
Certainly makes sense to run those functions sandboxed in WebAssembly, since the function code is user-provided.And then, yeah, I can imagine the process management making up a good amount of the complexity of their backend code...