That new definition covers off the majority of 8 bit micros (to the best of my knowledge) but I believe the CPC 464 Plus (read: not the regular CPC 464 but a later gaming model) couldn't be extended by it's cartridges; and frankly why would you need to as it had its own expansion port in addition to the cartridge slot.
I'd also like to add that I wasn't quibbling over the definition of "cartridge". I understand the term is quite broad but I am happy with that recognised definition even if it isn't a technical description. I know us engineers have a need to describe technology but not everything needs to be jargon.
I was just trying to inject an interesting angle to the discussion, not trying to be precise about what they are. It was an interesting characteristic they had for a while there. Personally I'm satisfied with "if it looks like a cartridge, it is", in which case absolutely yes the Switch uses cartridges.
I'd also like to add that I wasn't quibbling over the definition of "cartridge". I understand the term is quite broad but I am happy with that recognised definition even if it isn't a technical description. I know us engineers have a need to describe technology but not everything needs to be jargon.