You have duplicated rather than extended your screen, right? If that is the case, then it is normal.
The Digitizer both Touch and Pen are separate from the Monitor and are Human Interface Devices (like Mice and Keyboards). They will be active unless you disable them from device manager or via the command line/powershell
Correct....This makes total sense! Though, I'm guessing even if I disable it in Devices, the digitizer is still being powered, just with no functionality.
I'm just thinking in terms of maximizing the battery when using external peripherals (KVM)