Well gitea/gogs also have code hosting, wikis, issue tracking, and while CI is not tightly integrated it is fairly easy to integrate. So the value has to come from something else :) GitLab has integrated chat and kanban boards so there is other cool stuff in Gitlab but it's not really any of your listed reasons.

Edit:

I would have to say if I were to choose GitLab the biggest reason would be the UI. The front-end just looks a lot better. If Gogs/gitea could get a sponsor to help clean it up it would be a lot more popular.