IMHO it's because in the phone world only a handful of people look good naturally. Another handful learns to compensate by using really complex lighting setups (akin to a real photographic studio).

And the rest of us are left behind. We can even look "approachable enough" for some people by showing your way to approach the world, how we talk, how we move. But all of that is way harder to capture on a static photo.

I personally look terrible in front cameras, and I have a hard time creating any kind of profile in a dating app.