I don't have a smart phone, so I haven't used a phone camera. That's not to say that I wouldn't.
As I see it, the phone camera is the descendant of the old box camera/brownie camera/snapshot camera. These originally had a fixed-focus lens consisting of a single meniscus element, a single shutter speed, and a fixed aperture (a round hole drilled in a metal plate). Around the later 1950s, a second, larger hole was added to allow more light for the slower color film.
We started to see more sophisticated snapshot cameras in the Kodak Instamatic line (and I'm sure there were others), when one bought a more expensive model. For Christmas 1971, I got a Minolta Autopak 600 that took 126 "Instamatic" cartridge film. It had a coated 4-element glass lens, a couple of shutter speeds, a good range of automatically set apertures, and 4-zone focusing. It inspired me to get more seriously into photography, resulting in the purchase of a Yashica TL-Super SLR a few months later.
Snapshot cameras became a lot more sophisticated with the 35mm "point-and-shoots". At this stage, snapshot image quality improved dramatically. Then came digital point-and-shoots, and they were eclipsed and succeeded by phone cameras, which are pretty damned good by snapshot standards.
This brief and incomplete history is only intended to illustrate a point, as there were other cameras appealing to other demographics, as well.
- Murray