And if you just need a great forge for your company's dev teams you are all good to go. OTOH if you self-host a popular FOSS project then all of the network effects of hosting your repo on Github are gone. If you are a quite large project, such as Fedora who chose Forgejo [0] then it is fine to have a dedicated forge. If your small library repositories are hosted on single-person or small community self-hosted instances, then there is a lot of benefit if the forges hooked into this larger software development social network.

[0] https://communityblog.fedoraproject.org/fedora-chooses-forge...