Five of a kind is a poker hand comprised of five cards of the same rank. As no standard deck has five cards of the same rank a wildcard is needed to form five of a kind. It is the highest valued hand in poker games using wildcards.

The Highest Hand

In traditional poker the straight flush is the highest valued hand. It is the most rare hand. With the addition of a wildcard it becomes possible to form five of a kind.

Most games with jokers use them as a bug, and not a true wildcard.

There are fewer possible five of a kinds than straight flushes. You can form this hand with each of the 13 ranks. That is, there are 13 possible five of a kinds (78 with two wildcards). Without wildcards there are 40 possible straight flushes, thus five of a kind is definitely more rare and it makes sense to have a higher value.

But since you need a wildcard to form five of a kind, you could also use that wildcard to make a straight flush. This means there are actually a lot more possible straight flushes than 40!