That's certainly fair but, probably because I often hike in winter, I really don't want to potentially end up in a situation where I have a serious issue if my phone fails. Though they're pretty reliable, phones just have failure modes that physical maps don't.

I don't worry about it in casual situations especially when there are other people around. Shoot a photo of the map at the parking area for a casual hike? Sure. But I like having backups when I can.