FWIW, My DB is around 500MB (200k posts, attachments in the FS) and the whole process takes about 30 seconds. The reason I do it this way is that if my server dies, I don't want to have to repair some tables form a corrupt DB and search for the stable ones - I want to just dump the whole thing into a new DB in one line and be back up and running. I use my datestamp filesystem script as well, and then just tar them both up into a big tarball that I use yet another script to grab with wget from my home server nightly.

I can see where this would be an issue for really big boards, but again that's why I posted it as a How-To and didn't make it into a plugin/hack.