Quoting Al Boldi [off-list ref]:

Sure, browsing is the easy part, but Version Control starts when things
become writable.

But how is that supposed to work?  What happens when you make some
changes to a file and save it?  Do you want the "git file system" to
commit it right aways or wait until you to issue a "commit" command?
The first behavior would obviously be wrong, and the second would make
the "file system" not operationally transparent anyways. Right?

By the way, the only SCM I have worked with that tries to mount its
repository (or a view on top of it) as a file system is ClearCase with
its dynamic views. And, between the buggy file system implementation,
the intrusion on workflow, and the lack of scalability, at least in
the organization I worked for, it turned out to be a horrible,
horrible, horrible idea.

Cheers.
-- 
Jing Xue