The difference is that you can statically link GTK+, and it'll work. You can't statically link glibc, if you want to be able to resolve hostnames or users, because of NSS modules.
Static linking itself doesn't prevent modules. There's https://github.com/pikhq/musl-nscd for example
Static linking itself doesn't prevent modules. There's https://github.com/pikhq/musl-nscd for example