These ones can, too. You just have to shoot blind/store to the memory card in the camera instead of the phone.
Absolutely. The only thing that gets me excited about the QX100 is the F/1.8 lens, as if there’s one seriously complaint I have about my phone’s camera, it’s the low light performance. But again, I can always just bring my DSLR with my “Nifty Fifty” if I’m going into a situation where I know I’m going to want better photos in low light. And really, I would never carry around the QX100 all the time, just for the “spontaneous photo opportunity” situations where I choose to use my phone’s camera at the moment.