> Losing the system due to power shenanigans is a risk I accept.

There is another (very rare) failure an ups protects against, and that's imbalance in the electricity.

You can get a spike (up or down, both can be destructive) if there is construction in your area and something happens with the electricity, or lightning hits a pylon close enough to your house.

First job I worked at had multiple servers die like that, roughly 10 yrs ago. it's the only time I've ever heard of such an issue however

To my understanding, an ups protects from such spikes as well, as it will die before letting your servers get damaged