we already have a finished attic anyway - but yeah we also have heating and ventilation under the roof - shorter route for the solar cable and more space downstairs in the utility room for laundry and supplies. So I think it makes sense to get them out of the way (=under the roof).
please don't forget to mention that you have a fixed staircase to the attic. Such a room can then possibly be compared to a basement. I don't know anyone who regularly uses the attic with a folding/pull-out staircase. Usually, stuff is stored there that you need at most once a year. And that usually doesn't require fairly constant temperatures.
But you can. However, there is definitely a difference between reaching it very easily via a fixed staircase, or having to pull out the stairs every time. I see Karsten's variant as a fully functional cellar replacement, just as easy to reach and probably a similar climate. But that is not the standard. I just wanted to point that out.
Of course, that is a comfort difference. Nevertheless, I think that somewhat younger people will also regularly use a warm roof with a fold-down attic ladder. The woman can iron there, the man can paint something up there, you can also store fabrics there, guest bed so....