GitHub is a closed silo — you can do with it only what the company chooses to let you do. Like Facebook. They can start placing annoying adverts, restrict what external systems you can integrate with, introduce charges for services that were once free, and change their terms of use in any way they like at any time.

Yes, they provide a useful service, for free. But you get sucked in, then you get locked in.

GitLab is open — you can move away to another service provider if the current one makes a change that you don’t like. You or your project’s team can host your own GitLab, integrate whatever integrations you want with it.

If you do open source software, put it on GitLab!