i do not get it too.
Why was this necessary? Everything worked fine. The romset from Smokemonster with the old firmware.
There are a few reasons:1. People who want to set official high scores were having trouble getting them accepted when using the multi because they were doing those scores on "modified" roms since on the old firmware all roms needed to be decrypted to run.
2. Any new CPS2 games that might be found down the road will work, as-is without relying on someone decrypting it in order to "prepare it" for the multi kit. Even as-is the new firmware gave us a few new rom versions that now run and weren't available before because they weren't decrypted.
3. While the team behind the decrypted rom sets that we had are awesome and there were no KNOWN bugs. that doesn't mean that there weren't any here or there that may have slipped through the cracks and were hiding in portions of the games that people rarely reach. Running 100% original code ensures that the game will run like a 100% original b-board.
In short, the new update allows the multi to run 100% original, unmodified, game code, where the old firmware required a lot of work to make each and every rom playable.
Even with the new firmware you can still run the old ROMs if you want to make use of modifications like free-play mode, etc.