It is definitely worth it for those who do their work on desktop computers, because if you are doing something very important and lose all that work due to a power outage, you will lose a lot of time and nerves to make up for it. I used to have a laptop that had a removable battery and I used to take it out and keep the computer directly on the power supply, but the model I'm using now has a built-in battery and I think that's better because it means it won't turn off just like that.

I agree that some things should be invested in, no matter how expensive and perhaps unnecessary they may seem at one point, they can very well pay off in just one moment.