Why as a datapack?
If you have a server for you and your friends where you can't add mods by yourself, you can use datapacks instead. Just download the datapack, open your world settings -> datapacks and paste it in. Do a fresh reload and done! Another reason for it being a datapack is, that you can it also works if Geyser is installed.
What does it do?
It allows you to put wood inside the stonecutter. Only blocks that are logically crafted with just one plank are inside the recipe, so doors still have to be crafted manually.