[hoeppnertill]

The reason for not including an SD card slot is that this second-class storage is said to confuse users. It mounts after the system sends the BOOT_COMPLETED broadcast and may be removed at any time. Consequently, some operations are (or were) forbidden, like installing apps on the sdcard. Explaining this to users is fairly hard and, by removing the slot, unnecessary.

With 64GB inbuilt, I don't really see that as a problem, but for my 16GB N5 and N7, it's annoying at times. Also, file transfer on Linux is... improvable. I use adb to push my music onto the phone. :P

[72deluxe]

But you explained it pretty well in three sentences! Doesn't seem that hard to explain. People cope with SD cards in PCs and laptops and they are subject to the same restrictions / problems, and everyone appears to cope with them.

Heck, even USB sticks can be removed whilst they are in the middle of writing (and I've seen people do it), and the OS will typically warn you. We haven't seen the removal of USB ports from machines with the same defence (although some PC manufacturers like to put clusters of USB ports all together so you can't actually plug in two USB sticks next to each other...)