Traditional notarization guarantees "not to be altered," while SIGN guarantees "it is true from the beginning," this difference is crucial.

At the end of January this year, someone asked me to help with an on-chain architecture assessment for a commercial real estate project in Dubai. It wasn't a full-time job, just a part-time proposal to see how to turn property rights into tradable on-chain shares. At the time, I thought it was quite simple, just contract design and permission layering, and I could get it done in a week.
On the fourth day, the project's lawyer sent a message in the group: "How do investors verify that the property rights of this building are real?"
I was taken aback for a moment, then realized that my proposal completely failed to answer the question.
I designed how the data is put on-chain, how it is stored, and how to prevent tampering. But the lawyer asked— even if the on-chain data is tamper-proof, how do investors know that the "original property rights information" written in is itself real? Blockchain guarantees that "records are not altered," but it does not guarantee that "what was written at the beginning is correct." These are two completely different things, and I had mixed them up before.