My weekend rides tend to be a bit on the obnoxious side. Lots of climbing and distance.
It is nice having a weekend bike that only takes that abuse. I would be replacing parts constantly on my nice bike if I rode it all the time and it would not function quite as well.
However, my commuter is a decent bike but the parts are much cheaper.
For instance, spending $10 on a fixed gear chain is much better than the $30-$50 chains my Tarmac uses.