Speaking for myself, I greatly appreciate the fact that it was moved to Github because 99% of all open source projects I've ever wanted to contribute to in the past have all been on Github. Kbin (and alexapy, on gitlab) have been the only exceptions.
And that's not even mentioning my work also uses Github for our internal repos.
Speaking purely selfishly, it's simply more convenient to be able to manage and track my time and contributions all in a single place, and I can't imagine I'm alone. I'm looking forward to seeing Codeberg's long-term goals of federation see fruit, but for right now it was simply an obnoxious extra hurdle.