Yep..it's mainly for the very short (usually) check in line instead of waiting in slow moving zigzag line for 20 to 40 minutes.
And yes, the boarding pass they email me can't be used in many places (maybe Dubai for EK), and of course the bags have to be checked in anyway, then issued with a new,hard copy,boarding pass, which is necessary to show in Bangkok, for example. I keep these carefully as they are hard "evidence" of my travels and "missed" 90 day reports (I know the entry and exit stamps are in the passport, but a bunch of collated boarding passes are easier, I guess.
Of course the check in staff had my passport for 5 minutes so could peruse my status at the destination.
But I've never been asked a single question by them....presumably because it's all kosher