I previously owned a Nikon DSLR (APS-C) and would not even consider using a phone camera in it's place.
No way, no how. Not for anything resembling professional photography.
In fact even if I thought phone cameras
could do as good of a job, I would use the DSLR anyway just out of general principle. I don't like this seemingly recent trend/idea of "DIY-everything" at the expense of paid professionals with specialized skill sets, experience, and tools, that really know how to use them creatively/effectively.
That doesn't in any way mean that I'm against
ALL DIY. No no, that's not what I'm saying at all. DIY has it's place. But for example when my (now wife) and I met with our wedding photographer, if he had said that his main tool was an iPhone (or Android, etc.), I would have promptly hired someone else. Incidentally, our wedding photographer used a MK III and did a great job.
For taking casual pics though, sure, phone cameras are a very handy tool.
When I do get my next camera, it will have a full frame sensor.