The other very special things are battery life and durability. It's going to be very hard to get a phone to both work screen-on for 12+ hours (or even 5-6) running the GPS on high res mode, readable in direct bright sunlight, and robust enough to be fine during most bike (and mountain bike) crashes. They also generally offer either a touchscreen that works properly with gloves on and when wet, or has physical buttons for all the functions.
Quality bike computers are specifically designed to fill a niche that smartphones just can't do, which is why the market still exists.
Strava, et al, work fine for a lot of uses, but as one gets into more serious riding a dedicated bike computer is the way to go. This is because of the hardware, not due to a lack of app to be run on a general purpose mobile.
The battery life is a big item for me. I use a Wahoo Element bolt and love it. It does everything I need, lasts all day, and the best part is my phone is not being drained in case I need it.
Quality bike computers are specifically designed to fill a niche that smartphones just can't do, which is why the market still exists.
Strava, et al, work fine for a lot of uses, but as one gets into more serious riding a dedicated bike computer is the way to go. This is because of the hardware, not due to a lack of app to be run on a general purpose mobile.