I have posted the procedure a few times over the years and the
reason I have is because most just do not change their fluid
[ why, is beyond me] ..
So, this is just a second best procedure that makes for both a better/cleaner job, and an easier way to push the caliper back in.
At least you get the main crap out and get to see the fluid condition...
Why it is never mentioned in DIY atricles has always been a mystery to me , as most brake guys all do this without even thinking about it.
Why NOT doing it should be the question.....

I think some are just fearfull that once they even get near a bleeder, they are in for the" AiR in the Sytem Nightmare "...