I've been using Photo for around a year now - previously used PS CS6. I still occasionally have to fire up PS and its for three things:
Automatic lens correction for non-raw images. If I've taken an image with a wide angle lens and want to correct for the lens, PS can do it, AP can't - I'd really like AP to be able to correct the image - particularly lens distortion - for JPEGs.
Working on "full size" plans. Occasionally, I'll have things like room plans where I want to see where I can put furniture. With PS, I can make the image 3500mm x 4000mm (say) at a DPI of 2. So when I use the ruler tool it gives me the actual length of something and I can add rectangles which are the actual size of the piece of furniture. AFAIAA, AP only supports a limited range of preset DPI setting and if I try and put 3000mm as an image width, it converts it to pixels - in a related feature request, the rulers only seem to be in pixels. For the "real size plans" use, rulers in inches/mm or cm would be very useful.
Using the scanner. I understand this difficult in Windows, but OTOH, PS does do it - I can read an image straight into PS from the scanner.
As requested; picture taken yesterday and processed through AP - one of around 200 processed in an hour.