~/.config/git/ignore and ~/.config/git/config is the proper place for your global git config and ignore instead of creating a ~/.gitignore_global and changing the config. IMO.

my dotfiles are a lot smaller at the root level taking advantage of the ~/.config/ for a lot more things.

the git exclude isn't used as much because it doesn't get committed to the repository so you'd have to recreate it each time you wanted to use it. that doesn't mean they're bad just why they are not used.