Much depends on experiences. We were very comfortable upstairs right from the first night and still 8 years later. I think train travel in our childhoods made us envious of those families who had berths. It was a real treat to sleep up the ladder. RVers who did a few years in tents may, like us, feel it is a real privilege to have a bathroom and a great bed indoors.
The cabover bed is large with extra room for things that are out of sight from the main floor. We each have a reading light. Nocturnal trips downstairs don't seem to be a problem. I go down 2 or 3 times, DW one or 2 of those times.
We are in our mid sixties; age and arthritis may change our minds.