What some might consider a 'beater' may actually have qualities that appeal to the commuter.
I don't feel I'm losing anything by commuting on a bike that isn't made of carbon fiber, lacks deepV rims with aero spokes, etc.
My frame is covered in retroreflective tape and wrapped in inner tubes; this makes it look contrary to 'nice and shiny' to a casual observer, but the tape makes me safer at night and the inner tubes keep me from getting scratches that might develop into rust; I wouldn't do without them.