I've seen a lot of nonfunctional bikes that serve as a commuting bike. That includes the guy who came to the coop without bearings on one side his front wheel and a locked front axle which he had been using to get back and forth to work for a year. The axle turned in the dropout and wore off the threads. The bearings weren't worn out but had been removed prior to his buying the bike. Once we replaced the bearings and the axle, his speed jumped to near the speed of sound after all that resistance training

And, yes, any bike can be used for commuting. I've used road bikes, cross bikes, touring bikes, cruisers, hardtail mountain bikes (knobby equipped), soft tail mountain bikes (knobby equipped), full dually mountain bikes (also knobby equipped), and even tandems as commuter bikes. I even have a neighbor who rides an ordinary from the Denver Highlands to Downtown and back...a drop (and rise) of about 1000 feet.