A UPS would certainly protect a device by maintaining its power at a certain level, would it not? Maybe I'm wrong about that! I was also under the impression that a UPS came with a power surge protector, but I see that's not always the case.
That's true because a UPS normally regulates incoming voltage besides providing an internal battery that lets it continue running if the power supply is cut. The surge protector, on the other hand, protects against surges or high voltage electrical spikes. I think it is important to have both.