Do you really need to upgrade your 3 year old iPhone if you think about it? Those are still quite fast and can do everything you need. To me it seems like a waste, but you do you.

Even upgrading from last years phone would be worth it for the ability to record spacial video. I want to start capturing 3D vids as soon as I possibly can.

It's just marketing - there are apps where you can already record spatial video such as record 3d. They didn't mention any improvement to lidar. You can even use any truedepth iphone if you are Ok making 3d video using front camera.

I have a 4 year old phone and I don't see anything worth upgrading. USB-C, yay! But I already have a Lightning cable at home, is that worth hundreds of dollars?