I've been a Godot hobbyist for years. Big factors for me at first were that it's open source and that it's lightweight. I started using it for those reasons, and then I found that the node system "clicks" much faster than Unity's model. Once you "get it", Godot is both very easy to work in and program for, and while it's not as polished as Unity, it's basically the perfect tool for solo hobby projects.