I think there definitely has to be a clear reason for doing it.
I do a lot these days because I have identified some very clear issues which need sorting, if I don't then it has a clear impact on my lifts and by extension the way the movement feels. I also know what added mobility in particular areas will give me in the future. So I do at least 30 minutes before each session, totalling 1:30 to 2:00 hours per week at least. Some weeks it'll be closer to 3:00 if I have time.
To narrow it down like that, makes it useful. Otherwise if it's done just for the sake of 'doing your mobility work' it's silly.
I'd also add ankles to that list, Al.