It's primarily a reference to various language selection dropdowns offering "Chinese (Traditional)" (which is used in Taiwan) and "Chinese (Simplified)" (which is used on the Chinese mainland). That difference arises from Mao-era simplification of many of the most common hanzi characters to make them easier to write or distinguish.

Mixed with, yes, the variant spellings and word choices (e.g. chips/crisps/biscuits) that make it apparent to British English readers when something is American.

I think my confusion is more from the implication that variant spellings imply "simplification"—even at a glance, simplified and traditional hanzi differ greatly in complexity, whereas I don't see how "chips" is any simpler than "crisps", even as a joke....

EDIT: Of course, it doesn’t matter one bit in the grand scheme of things—feel free to ignore my pedantry over a silly joke :-)