Tires with different codes are different from each other. I can tell you that the Michelin PS2s (N2) for my 911 are different from the the PS2s made specifically for Cadillac ( same size). The PS2s for the 911 have a wider tread and start out with a slightly shorter tread. I learned this when researching replacements when these were in short supply.It started out with tires meeting the official Audi spec being stamped “AO” for “Audi Original”, and Mercedes “MO” for “Mercedes Original“. It has all gotten a little silly from there. Usually so long as a tire has the same spec (size and load rating) it is identical and you can ignore the stamp.
The same is true for EVs to an extent. The spec will have an unusually high load rating and this is much more critical than an ICEV (an ICE wagon will require a high load-rated tire in case it is fully loaded whereas a BEV is always heavy). The main feature of an EV rated tire is that it will be much quieter because tire noise is much more noticeable in an EV.
It is not a gimmick. Tires are often optimized for different car models. Further, if a tire model ( non car model spec) is sold through Costco or some other large retail outlet, it is not exactly the same as the tire sold at a dealer or smaller tire centers.
Yes, you can use the same model tire with a different or non-existent car code but they might not give the same mpg ( or range) or sound the same or handle the same or ride the same.