I agree phone is the wrong term.
But I reckon they are useful for much more than taking photos.
I also use the camera quite a lot because its handy but if I really want to take proper photos I still use a proper camera.
The greatest use by far for my mobile is as a portable audio device. I only have about 40 music "albums" on there at the mo (usually I have around double that) because I am gradually my old phone with the dud battery into an MP3 player for use in the shed.
I do get through about 3 audio books a week while walking the dogs, driving and laying awake at night - I haven't read an actual paper book all the way through since ~2013?
The other thing I use it quite a bit for is its measurement capability e.g. the Sound Pressure level meter Although I have non-phone versions of the same meters I'm not carrying those around with me all the time. The and the air flow meter, tilt meter and vibration analyser get occasional use.