The Risk of GLD and Gold ETFs

The recent Ukraine crisis and rise of the gold price bring the risk of gold ETFs to my attention. Investing in gold ETFs such as GLD, IAU, and SGOL is obviously more convenient and cheaper than buying and selling physical gold bullion. A newbie investor like me might think such paper gold investment is safe. After all, ETFs such as GLDM claim that they put their physical gold bars in an England vault.