It's not about efficiency or performance, it's about not having to own the iPhone in the first place. Just put a SIM card inside the laptop and forget about it.

It's not about efficiency or performance, it's about not having to own the iPhone in the first place. Just put a SIM card inside the laptop and forget about it. Windows laptops can even seamlessly switch between wifi and LTE depending on which one is available. But of course Apple would never allow that because they want to force you to own the full set of Apple devices. Laptop being self-sufficient would be against their policy. Not to mention that in the US the cell phone carriers artificially limit tethering speed or put data caps on it when you tether from your phone. You have to buy a dedicated data-only plan and modem.