For values of "ignore these releases" which are equal to "click remind me again later" every day, for each frequently released auto-prompting bit of software.
You're right that people want bugfixes, decreased memory usage, etc. But they may or may not want the assortment of other changes that come bundled with them, plus potentially being forced to debug "$FOO changed, so now $BAR doesn't work with it any longer" type interactions on a regular basis. (The ESR style model, plus a rolling release, is arguably the solution to these two use cases. But at least for Mozilla the ESR version seems to be a "please don't run this version" release.)