It's an individual thing, some people have to make sure everything is in proper order and some just don't care. Some in fact prefers it out of whack as that becomes artistic in a way.
I had my screen calibrated and using printer and papers which I had ICC Profiles, still the WB reference is a preference thing. I like to see what is it without proper WB and what it is with. I agree that most of the time one of the in-camera WB should work well.
But, come to think of it, is it really that hard to take an extra shot or two and in PS with several clicks you can see what the differences are? well... to each his own, I won't comment on what others think as what is important in what I want to get out of it and I want to be able to see how accurate my judgement on WB is and to do that I need a proper WB reference to make the comparisons.
No right or wrong answers here just that different people have different agenda and targets/wants/etc.. etc..
../azul123