It's a common interface, but you can still distinguish which of multiple devices...

glandium on Aug 5, 2015 | parent | context | favorite | on: Pointer Events Now in Firefox Nightly

It's a common interface, but you can still distinguish which of multiple devices triggered the event (with pointerId) and distinguish what type of device it was (with pointerType, which can have values "pen", "touch" or "mouse").