As alluded to by Charles, find out what bonnets they have. Do they have enough? Locally there are 3 types-Final buffing (synthetic wool), waxing/polishing (terry cotton-not plush, could induce swirls depending on products/technique used), and a "paper-type" applicator bonnet (basically for applying final wax, as there is no nap to it.) There are also foam bonnets, but these aren't usually in the "starter pak", so unless they've decided to diversify, chances are good they won't have one. None of these are of particularly high quality (for concourse finishes), but if you are using it on "beaters" that aren't going to be cared for afterwards, the owners probably won't see anything wrong. If you were to be using a 1-step, using a buffer can let you work the product more evenly, longer, and result in a thinner coat to buff off, while saving your shoulders etc.
As mentioned, it won't remove marring, but it also isn't likely to destroy anything either (I'm saying "likely" because there's always somebody that can find a way of screwing up something.)
I would consider trying it, as long as you've got some clean bonnets available. I've used them before and they can save you some effort. And as mentioned before, if you don't like it, you don't gotta keep using it.
