Not only is the iPhone always in your pocket, but it’s easier to carry and deal with.

I remember hearing a story from a well known photographer about a trip he took with a few others, including his wife. They woke up early to head out on a small boat in a lake or something. He was lugging all this gear and having to put a lot of focus into tuning the settings on his camera, he was pretty miserable. Meanwhile, his wife was enjoying morning with no baggage and snapping pics with her phone. She ended up having the best picture of the day, while actually enjoying herself, by not being bogged down by the gear.

Dedicated cameras have their value, but it’s been decreasing for years, and requiring higher and higher levels of skill to make it worth it. Most people could improve their photos dramatically by learning about framing and light, while just using a phone. These things have a much bigger impact on the resulting photo. A professional with an iPhone will always take a better and more interesting picture than an amateur with a DSLR for this reason.

Those sound like the 2 extremes, though. You don't have to take a lot of gear or tune a lot of settings manually with dedicated camera if you don't want to, but it's an option if you want to have more control or go for the ultimate quality.