Apple pen or I watch the biggest cost for use ratio

Pen discharges and is found flat when you want to use it.

The I watch needs similar charging to function

So it is usefulness to charge time that counts

The apple pen will charge with the USB 3.0 lightning port in 15 seconds for thirty minutes run time.

But who would want to look at your watch and wait 15 seconds before the face lit up to tell the time?

It is these facts that cost.