The CD32 uses EEPROM for storing non volotile data.
It would have also been the ideal choice for storing the A3000 SCSI controller settings, but the Ricoh real time clock happens to contain 26 x 4bits of battery backed RAM which wasn't being used otherwise. So I guess Commodore just chose to use it as it was there for the taking.
More information on battery replacement, etc
here.
