Apple could potentially force users to use a proprietary apple USB c charger instead of any random one. This can be done via a lockout chip inside of the cable itself that only apple produces and is already done on apples lightning cable (super cheap sketchy cables may not charge or have features missing).

Additionally the USB c port on iPhones will only run on USB 2.0 speeds, a standard from the year 2000 (yes, 23 years ago).