Because one is the standard nano sim and the other is e-sim.
Carriers will use the nano sim just like every other phone, from my reading only 10 providers in the world actually support e-sims (outside of the number share functionality for apple watch).
Hard to say if they will, but seeing that the device has a nano sim physical slot like every other phone i dont see a need as such.
The service is still being delivered and your free to find a secondary provider that accepts esims.
Esims add a further layer of complexity that has to be infegrated into a carriers network and this comes at a cost which would be passed down to the end users.
How would optus block the esim - thats tied to the device.
Optus would provide you a nanosim in order to use the service.
In the future when systems are upgraded then we will see esims being used.
Had a look on Telstras facebook page and some of the questions asked by their customers about esims in new iphones are met with "dont have any information about it and asks you to register interest"
Just confirmed with Optus that I can have my personal number requested for numbershare to use in the eSim & the business number I'll just use the nano sim for business number, it will be a godsend..
And they probixed up with esim for apple watch.
Optus does not offer dual SIM capabilities.
@Dan_C perhaps if your awake you could check with someone at Optus