What items would you even use this on, and what benefit does it have over just buy low/sell high?

Malicious is the wrong word for it, but short selling is detrimental to stock holders. You're betting on a hiccup while doing something that fuels that hiccup. The money you make in the process isn't from nowhere, it comes from other people. You add nothing to the system on the investor or investee side, you just weasel yourself in as an unnecessary middle man to take a cut.