Basically as the title says. We have semi frequent power outages where I live. The noise machine in my daughter’s room goes out and wakes her up. If I were to buy a USB powered one, plug it into a power bank like one of those 10000ma ones you get for charging cell phones, would it have continuous power. Basically like a cheap UPS
Check out the power bank reviews from the channel “Allthingsoneplace”. He does excellent reviews, pretty much exclusively focused in the technical side, testing efficiency, protections, etc. He also tests if it would work as an UPS. Most dont work and turn off after a while.