If the data originates offline - e.g. paperwork for an aircraft part - you still need to trust whoever puts the data on the blockchain. Are they who they say they are? Are the documents trustworthy? The blockchain ensures tracability after data is on the blockchain, but not that the initial data makes sense.
So if you need to verify these aspects manually at some point, might as well have everybody work through a regular API.
However, in case of a digital currency - e.g. bitcoin - everything is generated on-chain. There is no crossing the offline/blockchain boundary. You can verify that data was generated according to the algorithm, and how it was used afterwards. This is where a blockchain is not necessarily replacable with a simple REST API.
I don't really understand how this works, but could it happen that another way of verifying is by multiple people submitting the same information? For example, the buyer and the seller of a part recording the transaction.
The comment is likely pointing out that the blockchain portion of this project is just for marketing and doesn't add much if anything to just having a database that people can pull from.
I'm not sure if that is entirely true though. The blockchain piece might provide the needed infrastructure, while providing needed authentication. I'm not really sure though to be honest. Maybe someone with more insight can point out whether the blockchain piece is really needed and helpful or just bloat.
If the data originates offline - e.g. paperwork for an aircraft part - you still need to trust whoever puts the data on the blockchain. Are they who they say they are? Are the documents trustworthy? The blockchain ensures tracability after data is on the blockchain, but not that the initial data makes sense.
So if you need to verify these aspects manually at some point, might as well have everybody work through a regular API.
However, in case of a digital currency - e.g. bitcoin - everything is generated on-chain. There is no crossing the offline/blockchain boundary. You can verify that data was generated according to the algorithm, and how it was used afterwards. This is where a blockchain is not necessarily replacable with a simple REST API.