Agree 100% with Ken's comments above - and I take the same gear (plus a bit more) because getting good photos is important to me, and one of the reasons I travel.
The newer iPhones can take good pictures. And there's an old axiom, "the best camera is the one you have with you when you want to take a picture." But when the going gets tough, phones are no match for a good camera (as noted previously, it's a limitation of the sensor). When conditions are right iPhones can take surprisingly good pictures. But under other conditions, they stink. Nevertheless, my wife loves her iPhone 7+ and I have to grudgingly admit it is light, small and often takes great photos.
As an example, we just got back from a trip to Sardinia. There are flamingoes there. My wife is crazy for flamingoes, and wanted nice photos of them. We saw some a couple of days, just before sunset. On my wife's iPhone, her photos were grainy, with little pink dots - those were the flamingoes she wanted so badly. With my DSLR and the 400mm zoom lens I had brought along just for that contingency: I got full-frame close-ups of these stunning and freaky-looking birds that looked incredible. When I showed her, she finally said she was glad I spent all that money on that expensive gear.
Now, I'll admit the camera (and especially that zoom lens) are heavy, on some days I got tired of lugging them around and questioned my sanity. The gear is expensive (quality stuff is). But when I needed it, it delivered.
It all depends on your priorities. I was glad I brought 3 cameras (DSLR, point-and-shoot, and iPad) plus extra zoom lens - each worked in different circumstances, and none of the three would have been able to get all the photos. Your priorities may be/probably are different, but for some of us, the weight, bulk, expense and hassles are well worth it.