Software updates are a kind of project heartbeat. The content of them is less important than the signal, "this project is still alive, and maintainers are fixing issues for people". If a project does not put out updates, then users may (understandably) worry that if they have an issue, it won't get addressed promptly. I actually don't think there is anything wrong with having time-based releases, and putting very lit…
But on the other hand, if the software is stable and no longer needs updating why force small inconsequential changes just to appear to be maintained? Just release when there's something to release.
I do find projects like Dwarf Fortress very charming in that there's an endless supply of new things to look forward to.