So comfort isn't so much a factor as logic.
I agree with you to quite an extent, but I find keeping your hand over the same 5 keys if at all possible is not the best answer for many. We've had this discussion here before:if you just had to run up and down a set of three adjacent keys, over and over fairly quickly, would you use 123, 234 or 345? Probably not 345 - ah, but if those three notes were immediately preceded by two lower notes, as in CDEFG-FEFGFEFG etc, you have to decide whether staying over those 5 keys is appropriate as you will then be using less appropriate fingers. And I think articulation has a lot to do with the decision too; one of my favourite sayings is "staccato is your friend" (the other three friends being rests, ends of slurs and repeated notes) as I believe that it's more important to be using appropriate fingers than to keep your hand in one place - appropriate fingers being of course crucial to comfort. If you're playing legato, yes, you need to do thumb turns and expansions and contractions, but any time you need to lift the weight (as in all of those "friends" I just named) is a suitable time to reposition for a more appropriate fingering - and this could be more frequent that many beginners suppose.