Well, I have gone full circle from a Nikon DSLR to a compact Sony RX100 to an Iphone 11 Pro and now back to a mirrorless, full frame Sony A7c with a huge 28-200 lens. However, photography has always been a hobby of mine and part of the fun for me in traveling is to walk around with a camera in hand.
I have travelled with just my Iphone on several trips and only rarely missed having a dedicated, large sensor camera. The newer Iphones are just so good that the only times you will need more is for low light or extreme telephoto (zoom) shots. Even if I have a larger camera, my Iphone is heavily favored and used in restaurants and for spur of the moment shots. Similarly, if I am out on a quick errand, the phone might pick up a nice shot I would have otherwise missed.
The Sony RX100 is used when I am cramped for bag space such as on a hike or bike trip. Sometimes I will toss it in a jacket pocket as well. After comparing shots from the Iphone 11 and the RX100, I can honestly say that you would not be able to tell a difference between images taken from the two until you really start to blow them up beyond 8x10 and, frankly, we rarely ever do this anymore.
So, why did I just invest (???) $3000 on a new camera system when the new Iphones are so good??? And especially after extolling the virtues of traveling with just the Iphone on other threads???
Well, I simply like taking pictures. I like controlling the variables of exposure, f-stop, exposure compensation and ISO. I enjoy walking around with a camera in my hands and started to miss that. So, for those trips when I have space in the bag and time to walk around, I will take a big camera as a supplement to the Iphone.
I have found that the bigger camera gets me thinking about my shots. This often means I simply sit down and wait for something to happen or some variable to change, such as lights or crowds. This actually lets me slow down and enjoy the environment more whereas I otherwise tend to simply take a quick Iphone shot and move on. Also, when my kids where younger, I did not have the luxury of time to get out the large camera, compose the shot and take several versions. The Iphone was a necessity during these times.
However, I have no doubts that the Iphone is, in reality, up to the tasks of my demands 90% of the time.