A crate is a very large chest with 64 slots
But it does more! It will continue to accept items even after it's full. But any items inserted into it will be deleted.
It could be used on automated mining systems to deal with the large amount of items you might get from them. It will keep a certain amount of them and delete the rest.
It's also a easy way to delete items by simply placing them in the trash can slot
Uses: Logs (any type will do), a chest, obsidian and an ender pearl