I know, it just makes no sense to talk about magnification measuring area size. So, just 1.5x instead of 2.25x area size.
Hmmm...I think it's created more misunderstandings than explanations,
I know you know how it works BC but,
many people "do" think that the FF sensor is 1.5X bigger than APS-c and it isn't, and it isn't a 1.5X magnification either, in fact it has become a common error... which is exactly why I wrote in the manner that I did!
So the supposed sweet spot is not so sweet as it seems, DXO's perceived sharpness ratings from FF to APS-c show that for the most part, FF scores are significantly better on FF than APS-c, often double (2.25 less a little) that caused DXO to take a lot a unmerited flack, many "still" think DXO have it wrong, the Angry Photographer fro one!
IMHO it should not be called the "sweet spot" but the "bitter-sweet spot."