I honestly believe that most modern homes are designed by young architects who focus on sex more than utility.
I know this to be true because the master bedroom is large and impressive and convenient to having lots of sex (or at least, imagined sex if the architect had someone to have sex with) but is impractical for all other purposes.
It is the only explanation for wasting 20% to 25% of a home’s space to a place that you merely sleep in.