Exactly zero new car buyers do so out of need, it is because they want to. There are plenty of used cars that still take you from A to B, and are always better for your pocketbook. Phones are exactly the same.
I didn't need to stop using my 6S, but wanted the smaller form factor of the Mini (I use my phone a lot one handed) and the significant (in my opinion) tech upgrades. So yes, I upgraded because I wanted to, not because I needed to. No way could I justify the cost - and I paid full price. Two months later I'm still glad I did. Fantastic phone better than the 6S in every single way.