There are zillions of threads on MN that are beyond trivial or discussing things no one really gives a toss over, (in fact I'd say 99% of MN threads fall into the category) so not sure why so many posters are getting their knickers in a twist over this one.
FWIW I do not understand people who wear knickers in bed except for period time. I wear a nightie, and hate PJs for the same reason I hate knickers in bed. Knickers are for day time under clothes. it's as if they think their vulva is dirty and needs to be covered up.