First, a main floor bedroom is a very practical idea whether someone uses it as their main bedroom or whether other family members use it on occasion as a place to isolate themselves from other family members (cold, illness, post-op, or restlessness, for instance). I imagine all of us have needed a place to get away from others when we were coughing or sneezing or spreading germs from the flu or a cold - or that other family members have wanted that for us.
Even if it was just a place to catch a nap or lay down when suffering from a headache, main floor bedrooms or sleeping areas are a great idea.
Main floor bedrooms can also function as a guest room, reading room, den, craft room, home office, or study. They can be maintained with traditional bedroom furniture (bed appropriately sized for the space, one or more dressers, tables, mirror, and desk), or a murphy bed, trundle bed, futon, convertible couch, or day bed can be used to save floor space and still provide sleeping accommodations when needed - whether every day or just occasionally.
There's no question that a first floor sleeping area in multi-level homes is a very functional and universal design idea, but it is not essential. If it does not exist, and cannot easily be created, other options are available that eliminate the upstairs from being a challenge.
There are various types of lifts available, and there are elevators - available in a variety of styles, sizes, and designs. Elevators are not just a luxury item like they once were. Now any home can have one - and all multi-story homes or ones with basements can benefit from having them. Elevators, while a more costly alternative than a lift, can add real value to a home and serve the needs of anyone in the home of any age or ability - truly a universal design feature!
By selecting and installing an elevator, the necessity of a first floor sleeping room can be overcome. In those instances where floor space just doesn't accommodate an elevator, there are small-footprint pneumatic elevators and ones that can be installed and enclosed on the outside of a structure - with interior access the same as an elevator entirely located inside the home.
Main floor sleeping areas are a great feature to have in multi-story hoes, but elevators make access to upper floors quite simple and add plenty of value to the home since future owners will appreciate them as well.