[BlackSolider]

....

The two are fairly similar: you can look at them, trade them, collect them, laugh at them, hate them, etc.

But there's one major difference between collectible hats and a collectible card game:

Cards you can battle with.

Thus making cards better than hats, imo. Whether you agree or not, cards still have that added function because you can't have a hat battle last time I checked.