As so often, 'None of the above'. I don't use my smartphone, because I'm not comfortable with the handling (to put it mildly). I'd sooner use a purpose-built camera.
On the other hand, I *don't* think smartphone cameras are rubbish: it's undeniably possible to get very good results, if you're prepared to take the trouble.
Whilst I have got a smart phone, from necessity more than anything, using the camera on it is just a huge Pfaff! and the picture quality, even with it being 13 mp is in my opinion rubbish, OK so its probably suitable for the rubbish people call photographs which are posted on social media. Long live the proper camera CSC/DSLR I say!
The same as John above in an emergency, on the odd time i have not got my camera
I don't have a smartphone and I don't want one because a lot of them don't seem to work well as a phone, and the sound quality is generally appalling. I have a super little Nokia C1 phone for making calls, and when I don't have my DSLR with me, I usually carry an ultra slim Panasonic Lumix DMC-XS1 digital compact which has a sharp 24 - 120 (equivalent) zoom lens and fits easily into a shirt pocket.
I don't have a 'smartphome', and my cheap pay as you go is only switched on when I want to use it, so GCHQ (or criminals with the technology) will not know where I am. And why restrict myself to only one lens, with no lens hood and no screw thread to attach an ND grad filter?
I've put 'Never, I think they're rubbish' - but I want to qualify that.
For simple, straight pictures, they're fine. Family snaps, great.
But I like using long lenses, and I REALLY can't be doing without an eye-level finder. So, in an emergency, I'll use mine - but I generally carry a 'proper' camera all the time, even if it's only a Fuji X-10. But at least that has a wide-aperture lens and a viewfinder!)