The big change that smartphones have made in camera use is that previously people took cameras with them when they were expecting to see something “special” — an event, on holiday — and took the photos, then when they got home developed the film (old days) or uploaded them to their PC (recent days) where they got looked at, maybe printed and stuck into an album which was brought out occasionally when reminiscing and shown to a few friends or family.
Digital cameras superseded film ones because of cost and convenience but the use model didn’t really change so much — if you didn’t take the camera with you deliberately, you didn’t take a photo, and even if you did only a few people saw them, usually much later.
This has completely changed, now people have their cameras with them all the time, typically they take photos (and videos) and share them on social media or online albums immediately, so many more people see them in almost real time.
Yes there are still a few people who use digital cameras, but mainly in a more professional mode — when you went out to a tourist attraction a few years ago everyone had compact digital cameras, now thay almost all have smartphones instead.
And the newer phones can take pretty good photos, even when viewed on an HD screen — maybe not quite as good as a high-quality digital camera, but then the slightly lower-quality photo you did get is better than the high-quality one you would have got if only you’d had your camera with you…
What this shows is that the vast majority of people would rather have a pretty decent camera with them all the time where they can share the results immediately (smartphone) than a better-quality one they only have with them when they plan in advance to take it (a digital camera), especially where the difference in quality for most people is pretty small and decreasing every year.