btrfs and apt

Here on debian wheezy (testing), I note the mighty apt is doing a pretty big dist-upgrade this am.
I think btrfs could bring a bring a great safety net to such things.
example..
Need to get 184 MB of archives.

~# apt-get dist-upgrade
Get:1 http://ftp.uk.debian.org/debian/ wheezy/main dpkg amd64 1.16.2 [2,327 kB]
. (etc..)
.
.
After this operation, 516 kB disk space will be freed.
Do you want to continue [Y/n]? Y
Create pre-installation snapshot with btrfs [Y/n] Y

That would enable a full rollback in case of any packaging hiccups?