Why Sovereign Gold Bonds are more popular and getting market heat?

Investors are going to get 2.50% per annum (Fixed rate) interest on the initial investment. Interest will credited semi-annually to the bank account of the investor. The last interest will be payable on maturity along with the principal. In such case if you are planning to buy physical gold for investment, this bond is giving same advantage + extra interest of 2.50% PA. As well as you can use this bound for collateral for loans.