Cryptography is disastrous to use incorrectly, and "make sure a prankster can't add suffixes to anything" is exactly the kind of property that's easy to screw up.

For example, have you ever run "git fetch" on a pull request? You just hashed files you didn't make, and stored them under their hash. Whoops.

Have you ever used nix? A distributed content addressing system? Validated something is safe then signed a hash of that thing? Anything where a file and its hash are assumed to be interchangeable for identification? If you just go looking, the world abounds with chances for mischief.