I understand bein_hasedorim’s post, 2)bnei Torah wear black & white because
they are respectable, & should dress appropriately,
Lawyers, etc. businessmen, (old school that is)
But personally, B&W always scared me on a personal level. Dress for many (tho not all) people is naturally a very personal and expressive inyan. We have so many guidelines on how to dress (tznius, not flashy, etc) that color is one way we can express ourselves individually while still maintaining dignity and uniformity as a nation. I personally frequently wear more color (shirts, ties) on shabbos or yom tov because of the way i feel and my natural tendency to express through dress (and I feel B&W all the time is just plain BOOORRRRIIINNNGG) but this is my own opinion and personal taste, others express their individuality in different ways, so B&W can work for them.