Rainman Count Coins
A player character can look at a pile of coins of any size and immediately accurately estimate how many there are to the most relevant significant digit as well as distributions. For example, a character could look at a chest and count that there are 300 silver, 850 copper in a matter of 1d3 seconds.
This skill gives no insight into the validity of the coins, just what kind they appear to be and how many there are. This makes dealing with treasure piles quick and easy (and therefore the game moves toward the action more quickly). Also, you do this in your game already. If you don't, you players probably hate you.