I saw a video which was shot simultaneously with an iPhone 7 and a RED Weapon. On my laptop screen there was almost no visible difference between the two. One is a 1000$ smartphone and the other a 50 000$ professional movie camera.
Does this mean the iPhone is as good as the RED camera? Sort of, but only if the conditions are perfect. Shooting great photos and videos with a smartphone is possible when the light is good and plentiful, when the weather is nice and most importantly, you know what you are doing.
The difference between amateur and professional equipment becomes apparent when the conditions go from optimal to less than optimal. A large sensor will let in more light when it’s dark without adding noise to the image. Professional cameras and lenses are often waterproof or at least water resistant. They offer more fine tuned settings to suit every situation.
P.S. Maybe you’re not a camera guy so here’s a car reference: a muscle car can match a Ferrari in a drag race but what happens when there’s a corner?