Some digital goods, such as gift cards, are held for a set amount of time before you can receive them. This is a security mechanism to prevent fraud which is very prevalent among digital goods.
The hold period is determined by a creator account's purchasing history and account legitimacy (this includes the number of gifts you've received, and the age of the account, among other things).
However, there is nothing to worry about because as soon as the hold period expires, the digital good will be released to you.
This measure, along with other fraud prevention measures, are designed to keep our community safe.