There are, broadly speaking, two kinds of designers in software.
- designers who come from an advertising/visual design/motion design/packaging/print (although those are a dying breed)/etc background.
Those people care more about how things look in a video commercial or on a giant billboard, and they care about visual aesthetics and making something that catches your eye because it looks really good.
- designers who come from an interaction/HCI/usability/accessibility/etc background
Those people care about things more from a systems point of view, how features will behave across a variety of contexts/modalities, how users come to understand them over time, etc. They had more of a voice in the 80s/90s (Don Norman, Bruce Tognazzini, etc are in that category) but have been increasingly in the minority ever since.
(Designers who come from an industrial design background are a bit of a wildcard - some will put superficial fit & finish above all else, while others really get how good ergonomics, tactility, etc can translate to software).
Honestly, there's value in both. Users will judge a book by its cover, and you want interfaces to look attractive and be compelling - designers from the latter group will be content with designing interfaces that just look like black and white wireframes.
But at the same time, you don't want pure aesthetics to run completely orthogonal to core usability. So it's a balance, and software interfaces are usually worse off when that balance is out of whack.
Anyways, I'll let you guess what category of designers are overrepresented in Apple's ranks. Hint: their current head of interface design comes from a magazine design background.