BTW, since I move all of my repo to SourceHut, I also paid (donate?) a small amount of money to them too. If you are a die-hard Mercurial user on SourceHut, please read and consider supporting them.
Quoted from https://veronneau.org/trying-out-sourcehut.html
I'm not sure I like the way features (the issue tracker, the CI builds, the git repository, the wikis, etc.) are subdivided in different subdomains.
For example, when you create a git repository on git.sr.ht, you only get a git repository. If you want an issue tracker for that git repository, you have to create one at todo.sr.ht with the same name. That issue tracker isn't visible from the git repository web interface.
That's the same for all the features. For example, you don't see the build status of a merged commit when you look at it. This design choice makes you feel like the different features aren't integrated to one another.
In comparison, Gitlab and Github use a more "centralised" approach: everything is centered around a central interface (your git repository) and it feels more natural to me.