I don't see any problem with it. I'm not sure I've seen any real evidence that warming and cooling cycles will really negatively affect beer, so I would not worry about that unless someone has some real evidence, rather than just speculation.
Bear in mind the energy costs however. Cooling a warm keg down to fridge temp takes quite a bit of energy, on top of what it already takes to keep it cold once it's chilled. I don't know exactly how much extra energy it takes, so it's hard to say if it's going to add much to your electric bill, but it's something to think about.