Your logo is branding that communicates at the reflex level. Think about, when you see a Ford logo, or a McDonalds logo, or a Nike logo, all the feelings and emotions and trust or distrust you have for that brand is all triggered by logo. Needless to say, they are sort of a big deal.
By providing the full gamut of logo design versions when you need a banner done, letterheads made, or enveloped printed you'll know the printer has everything they need.