>Maybe I'm a whistleblower with thousands of files, but I don't want to release them all right now. This tool allows you to easily prove that a file you release later was part of the original collection.

That makes it more concrete. Thanks!

>Another use case might be an organization that has a large archive of important files. This tool allows them to efficiently sign all of these files by signing the root hash.

This one, I'm still a bit confused. Sign them for what purpose?

If they're signing a bunch of documents to vouch for their authenticity, don't they have to cryptographically hash all the documents anyway? Or is the idea that instead of hash+sign N documents, they hash N documents, but they only have to sign one thing?