They do font-display now, so the reasons are dwindling. Especially because they have caching you don't have, server speed you don't have, and can do fancy server-side optimizations.

But with self-hosting you can do fancy stuff like subset and pre-load.

Little helper app:

http://google-webfonts-helper.herokuapp.com/fonts/aclonica?subsets=latin

(We have article on this:)

Don't just copy @font-face from them directly