Absolutely agree that intonation needs to be regularly practiced and checked up on. However, if your intonation is good enough to the point where your bandmates and the audience don't notice slightly off notes, you'll probably make yourself an even better musician by focusing more time and effort on something else.
I know my intonation could be better. I cringe when I make mistakes. But virtually no one but me notices so there are
other things I can practice more that will pay off bigger towards making myself a better bassist.
That is definitely a valid point. However, for me, on upright and fretless, intonation is number 2, after feel. Feel is something that really can't be practised in a traditional sense, so during my practise sessions, intonation takes a good bit of my time. I like to really focus in on what I'm doing, technically. I work on other stuff, constantly---but I make sure that the new stuff is in tune.
Different strokes et cetra et cetra. Neither of us are right or wrong.