Apple senior vice president Phil Schiller explains to The Independent why the company made certain design choices, such as dropping the SD card slot in the new MacBook Pro:
Because of a couple of things. One, it’s a bit of a cumbersome slot. You’ve got this thing sticking halfway out. Then there are very fine and fast USB card readers, and then you can use CompactFlash as well as SD. So we could never really resolve this – we picked SD because more consumer cameras have SD but you can only pick one. So, that was a bit of a trade-off. And then more and more cameras are starting to build wireless transfer into the camera. That’s proving very useful. So we think there’s a path forward where you can use a physical adaptor if you want, or do wireless transfer.
At the risk of going on anecdotal evidence, I’ve only ever owned a single Mac with an SD card slot, my 2011 iMac. And I’d say on that machine I used the SD card, oh, fewer times than I used the optical drive. A lot fewer. Are there people who will miss this? Absolutely. But I don’t think it’s a decision that will affect most MacBook Pro users.
Schiller also addressed why Apple left in the headphone jack, after making such a public display of removing it from the iPhone 7:
These are pro machines. If it was just about headphones then it doesn’t need to be there, we believe that wireless is a great solution for headphones. But many users have setups with studio monitors, amps, and other pro audio gear that do not have wireless solutions and need the 3.5mm jack.
As to whether those two statements are contradictory—in terms of losing the SD card slot but keeping the headphone jacks—I’d say not entirely. For one thing, I’d bet way more people connect external headphones/speakers/etc. to the headphone jack than use the SD card slot. More to the point, though, the SD card slot probably takes up a lot more room inside a MacBook Pro chassis than the headphone jack. (I’d also guess that in general there are more options for those looking to get data off an SD card than for those looking to connect a sound peripheral—with the exception of Bluetooth headphones.)