Regarding low light sensitivity I disagree with DSLR requirement. [...]
The ISO sensitivity of the iPhone 12 is about 5,000 - which is extremely good.
But the massively larger sensor in a modern full frame DSLR blows it away by an order of magnitude, e.g. Nikon D850 max ISO is 51,200 for comparison.
[...]
Killer for DSLRs is lenses and if you need to print large format. Everything else, fuck it, not worth it now. Expensive, fragile large, heavy. A lot of the photography I do is out in nature which is a chore to lug another 2kg of crap around on a 20 mile hike into the middle of nowhere. Plus by the time you've got the thing out, the moment is gone.
Agreed. The best camera in the world is... the one you have with you!
I rarely take the DSLR out for a spin these days, the phone camera is "good enough" even in my lowly Galaxy S5.
The only issue is that as you zoom in with the phone camera, it is obviously digital zoom and quality plummets rapidly as you zoom. The good news is that most photos in social settings benefit from the good wide angle performance of phone cameras, so it is rarely an issue.