If your IP (and possible your browser) looks “suspicious” or has been used by other users before, you need to add additional information for registration on gitlab.com, which includes your mobile phone number and possibly credit card information. Since it is not possible to contribute or even report issues on open source projects without doing so, I do not think any open source project should use this service until they change that.
Screenshot: https://i.ibb.co/XsfcfHf/gitlab.png
Even just for reporting issues, anyone who is capable of identifying a bug is likely to have a GitHub account. Not so for Gitlab or others.
Then you’ve got seamless integration with Vscode as a bonus, it’s more like why would you not use GitHub unless you have a specific problem with them.
If you really want to, you can add a “log in with Github” button to your Gitlab server: https://docs.gitlab.com/ee/integration/github.html
I was asked to report bugs by people without github account several times, so you are wrong.
Does GitHub still only permit one account? I remember looking into it awhile back and not wanting to get things mixed up between personal/professional arrangements and the one account policy put me off.
congratulations then, it supports multiple accounts, haven’t used it yet though.