I don't think it makes any sense to mention source hut because none of the features you mentioned are killer features (or relevant. Why should I care about implementation details of feature tracking?) and it completely fails to address GitLab's main value proposition: it's CICD system.

Anyone can put up any ticketing system. They are a dime a dozen. Some version control systems even ship with their own. CICD is a whole different ballgame. It's very hard to put together a CICD system that's easy to manage and has a great developer experience. Not even GitHub managed to pull that off. GitLab is perhaps the only one who pulled this off. A yams file with a dozen or so lines is all it takes to get a pipeline that builds, tests, and delivers packages, and it's easy to read and understand what happens. On top of that, it's trivial to add your own task runners hosted anywhere in the world, in any way you'd like. GitLab basically solved this problem. That's why people use it.