Apple's theory on removing MagSafe is that their laptops now provide enough working time, and charge fast enough, that it is rare that people will need to work while plugged in. This is clearly influenced by their experience with iPhone and iPad. It's also why they felt fine with silly-looking charge orientations for their mouse and pencil.

Is it wrong? We'll see. I think a lot of people work with their laptops plugged in as a matter of habit rather than necessity. That doesn't make it wrong, though.