If you can afford a 320W CPU in the first place, you can probably afford the batteries to power the thing for a few hours, but it does still add a considerable amount to your backup costs.
And it might be hard to get your system configured to throttle itself quickly enough when the power goes out: having the UPS connected over USB to a userspace application that monitors it and changes Windows power plans in response to going on battery could be too slow to react. It's a similar problem to what gaming laptops face, where they commonly lose more than half of their GPU performance and sometimes a sizeable chunk of CPU performance when not plugged in, because their batteries cannot deliver enough current to handle peak load.
I switched from a 5950X + 3080, to a 5700G APU, to finally an M1 MBP + Steam Deck last year for this exact reason. Far cheaper to have a 250wh battery that can handle those two for the ±2h outages every day.
Now you shift goalposts to saying you should only care in data centre contexts, in a thread discussing a desktop processor.
It's okay if power consumption doesn't matter to you, but that doesn't mean it doesn't matter to everyone. That's why it's important to have these metrics in the first place and ideally to try and optimise them.