A big reason we did a "fix week" at my old job was to deal with all the simple, low priority issues. Sure, there were high severity bugs, but they would get prioritized during normal work, whereas fix week was to prevent death of a thousand cuts. Kinda trivial things that just accumulate and make the site look and feel janky.

Some things turn out to be surprisingly complex, but you can very often know that the simple thing is simple.