No iPhone app, the sensor uses NFC. I read Apple is opening up NFC to third parties so it could be coming.
The software-defined 10 (or 14) day lifetime limit has always bothered me. It is almost an ethical thing if the device can reasonably operate longer, which seems to be the case from the 3rd party apps.
I don’t think most CGM users would switch, except perhaps due to cost. It’s pretty small too. The main benefit is for someone who has never used a CGM to see the effect of food, exercise, etc.! I read you need a prescription in the USA but even if insurance doesn’t cover it, for a couple hundred bucks you could try it for a few weeks and learn some patterns.