This is protection, in the form of insurance, for the buyer in the event that the seller does not have full legal rights to the property.
Before a real estate transaction is completed, a title search is done. The insurance is taken out in the event there is defects in the legal ownership of the property.
One of the claims by proponents of blockchain as it applies to real estate is that disputes of this nature can easily be cleared up. If properties were tokenized, the ownership chain is firmly established by the ledger. One simply needs to have the private key to the token along with a valid claim. Of course, mechanisms will need to be put in place in the event of a hack or someone stealing the private key.