In the US there are laws or customs as to counting bedrooms for some purposes. In some places, at least, a bedroom must have a recessed or walk-in closet.
In my house there is a room that would be listed as a bedroom, as it has a large walk-in closet, but I use it as my library/office. Off the entryway, near the powder room, there is a room that would not be called a bedroom but rather a study or office or some such thing, even though it could be used as a bedroom, with some inconvenience.
As far as I know, houses and apartments are never advertised as having some number of rooms but rather some number of bedrooms by that definition, regardless or current or prospective use, and some number of full or half bathrooms. Kitchen and some sort of living room or family room is assumed (apart from studio apartments). Studies, dens, separate dining rooms, both living room and family room, media rooms, recreation rooms, wine cellars, etc. would be mentioned separately. I have a laundry/utility room that probably wouldn't be mentioned in a house of this size. Especially for apartments and condominiums, square footage would get prominent mention.