As opposed to unallocated gold, allocated gold is assigned entirely to its owner but kept elsewhere, usually in a vault. The benefits of holding allocated is that it cannot be lent out to anyone else or form part of a pool which prevents it from being claimed by any one individual. Having allocated gold in a vault solely with your name on it means you can redeem it entirely at any point. It also allows you to use that gold as money, because it is counted, registered and legally owned by you it can be instantly spent worldwide using a Mastercard.
Other forms of gold holdings such as having the physical metal at your home or having unallocated gold in an investment portfolio do not allow you to do this.