I think it's not "zooming with the sensor", but has a slim lens stack to enable optical 2x zoom. The whole system is also PDAF, so they need the movement anyway.
Same thing with the new modem.
I'm a bit suspicious about this, because if it was truly great, they would have waited longer to advertise it as a must have feature for their "pro" devices.
It's sort of beta testing the thing on the lower volume product with less tech literate people who won't complain too much because of some weird connectivity issues.
If it performs, Apple is going to make even more money on the next round of iPhone, not that Apple needs any more money but you know, if that could stop them from increasing the price, that could be nice.
Since Apple owns the whole stack, they can iterate faster too.