The most underappreciated part of the article is the risk stated below:

Title registry still dependent on the statal entity

I don't know about elsewhere, but in the United States, land records are actually handled on a county basis. I have nearly a decade of experience working with counties to allow electronic transfers of property, and many of them just don't like the idea.

Even if a county accepts electronic submissions of land records, Propy may not be authorized to transfer property. As an example, the article mentions real estate in California offering portion of revenue. No, it won't, because to submit a deed to the ERDS (Electronic Recording Delivery System) in, lets say Los Angeles, according to state statute, you have to be a lender (bank/credit union/etc) or title company (that issues title insurance).

As I said, I am not familiar with international real estate, and they may have huge success outside the United States, but within the US, they will be limited to rental markets. Another point I will bring up is that existing banks already have a system called Mortgage Electronic Registration Systems (MERS) which tries to do this same thing of creating a parallel registry system. You can read about it in the MERS Wikipedia article. As the article points out, courts have found many aspects of a parallel registry to be problematic and ruled against it in many cases. Without the deep pockets of multiple, large international banks supporting it, it would fail.