A UPS does do more than merely cover actual blackouts though. The mains do not have to have zero voltage before a UPS kicks in. Usually they would be set to something like (assuming 110-120VAC mains) 80-90VAC for them to kick in, even for a second.
Ever notice your lights very slightly flicker when say your AC / fridge turns on? That's a brownout, and a UPS will also protect you from that. While the brownout may not be enough to cause an actual shutdown, it *may* be enough to slightly corrupt memory, etc
Of course, regardless of whether you have a UPS or not, you should try and ensure that the power going to your server(s) is as clean as possible: Ideally on its own separated line with an isolated ground, and definitely not on the same line as any major appliances in your home.
And if you're hot during a lengthy power outage, then get a generac not a UPS. Use the appropriate device...