It's more that it provides more control on the centralized<->distributed spectrum. Git by default, yes, is fully distributed with every copy of a repo supposed to maintain full history, etc. GVFS allows you the option to offload some of that storage effort to servers you specify. Those servers can be distributed themselves (similar to CDNs, etc), so there's still distribution flexibility there.

You can think of it as giving you somewhat flexible control of the "torrenter/seeder ratio" in BitTorrent: how many complete copies of the repo are available/accessible at a given time.