Not the original answer, but I also have a couple of mice (elasto) - one for each hand, and then between my split keyboard I have a trackpad.

As much as possible I avoid the mice but when needed it's good to have the option of changing between hands.

Maybe one is a decoy for the cat

Not OP, but I use 2 mice. I use a KVM, but have one dedicated monitor for my work computer so it's always visible (and 2 shared amongst other machines). So I have 1 mouse on the KVM, and one on my work computer so I usually don't have to switch out of my non-work session to deal with something that pops up on the work machine. Also have a programmable usb 10-key with some canned responses. And, no, I can't remote into the work machine from the personal machines (regulated industry).

one for each hand, it takes getting used to and i have hunch it changes you, neurologically