Sure it is, if it has connector pins meant to be used to plug it into a larger unit for interface.
No so
. Cards that plug into a mother board, be it ram, video, nic, sound, etc - are not cartridges. They are cards. A cartridge is a case that encloses something, be it bullets, pills, PCBs, etc.
Yes, it is. Yes, it does. Rip apart a HuCard some time. Only a very small percentage of its mass is actual ROM.
I've taken apart many hucards (swapping around the PCBs to play tricks on friends). The plastic
card does not enclose the PCB. It's glue to the under side. That's not enclosing or encasing a PCB.
A car is not a truck, but both are vehicles.