Yeah, direct pairing is basically not an option. You need the CAN bridge to actually use the car (safely). There's a bunch of other things that end up not working when you do a nonidentical battery swap with the direct pairing method, like your AC/heater not working, the brake system tripping up every so often and excessive battery drain due to the battery CAN messages not stopping and keeping the CAN system alive when the car is off.
The batteries are mechanically compatible and the connectors are identical, but that's really where compatibility stops. And there's not just compatibility issues between battery generations; within generations there are pretty significant firmware differences. The first few UK and US battery swaps we've done with our kit ended up not being able to (properly) QC, which ended up being a firmware issue. Then a Slovenian (also US import) car came to us and had a whole bunch of other weird LBC/VCM-related quirks with a battery swap. You end up needing to do quite a lot of subtle stuff to make everything work, and even then we've now resorted to installing an extra CAN bridge on the CAR-CAN side to fix some (quality of life) display issues, like fixing the horrible GOM when increasing battery capacity, fixing the battery health meter and fixing the battery bars to actually work linearly.
The batteries are mechanically compatible and the connectors are identical, but that's really where compatibility stops. And there's not just compatibility issues between battery generations; within generations there are pretty significant firmware differences. The first few UK and US battery swaps we've done with our kit ended up not being able to (properly) QC, which ended up being a firmware issue. Then a Slovenian (also US import) car came to us and had a whole bunch of other weird LBC/VCM-related quirks with a battery swap. You end up needing to do quite a lot of subtle stuff to make everything work, and even then we've now resorted to installing an extra CAN bridge on the CAR-CAN side to fix some (quality of life) display issues, like fixing the horrible GOM when increasing battery capacity, fixing the battery health meter and fixing the battery bars to actually work linearly.