The idea is great, but if we look deeper:

 - Gold has value other than value as an asset, so it is possible to dissolve gold and reuse in things such as women's accessories, industry, medical purposes or selling in the black market.
 - Gold is one of the secrets of countries, so the use of a technology based on transparency such as blockchain threatening to reveal those secrets.

In general, blockchain technology can play an effective role as a protection for such assets