It is too easy to hold physical gold and silver; why bother with certificates?
People don't have to bother with taking actual delivery of the gold, storing it properly themselves with adequate security, paying delivery charges, or having to carry the insurance.
This disadvantages are manifest.
They also tell you this lie:
"An allocated gold account means that there's a certain amount of gold held that directly correlates to the certificate. If you hold an allocated gold account, then you technically own specific gold bars that are held by the issuing bank. Those gold bars cannot be allocated to anyone else or used for any other purpose by the bank. They are, essentially, looking after your gold for you.