I maintain some small open source projects (which I wrote for my own benefit), and judging from GitHub issues and stars, get some use.
But I have absolutely no idea who's using the software, or which subsets of features they care about.
I'd happily put work in to improve things users cared about, but have no idea how to get that info (I don't know who they are so can't ask), or using telemetry (which I'm loathe to add due to its perception).