You're not considering all of the different ways in which a form can be used. Not all forms are simple "type in your name and address" sorts of things. The form might be displaying some complex data that the user is expected to edit, and a Reset button can save you a roundtrip to the server (and therefore be a lot faster, and improve the user's perception of the responsiveness of the page or application).
Since I don't know what sort of form the original question is regarding, I won't venture to guess whether a Reset button makes sense in this case.
Linda
