> How would an NFT be better than the above database in any way?
It wouldn't depend on the benevolence of a third-party absorbing the cost of running the index.
It would be geographically and culturally agnostic. Zoom out here and notice how little of the World's population is involved: https://map.bikewise.org/#0/84/-77
It would be globally unique and would not require the cooperation of manufacturers. Neither of my two bikes has a serial number because they're 'too old'. Other bikes have conflicting serial numbers.
It would eliminate the privacy and security risks of maintaining a central database of PII and associated valuable assets.