Is there any sort of premium/collectibility to this coin or are these somewhat more common than I'm thinking? I've searched at least 15 boxes of Pennie's and this is the first time I've seen on like this.
Sometimes the grease strike will partially obliterate the design, while at other times it will completely do so. Grease strikethroughs are very common for the most part, and only grease strikes which have obliterated large areas of the coin have any added value such as yours. The exception are coin series which are rarely found with errors of any kind.
This type of error coins occurs when grease gets on the planchet or die and is struck into the coin. The grease can come from any number of sources including the minting press, which has lots of moving parts that get oiled, or it could come from the planchets themselves, which historically have at various periods in time been coated with a small amounts of oil.