I too consider it part of branding the product. Then the question becomes how are you going to design your business card, your blog and how do you package your product. All of this is branding and presents a consistent, easily recognizable look to present to the buyer. Just my opinion. (Oh, I'm on my 4th rendition with one more tweaking to go.)
It may not appear to give you immediate sales but as you build your business exposure, I think it will definitely make a difference--especially for the buyer sitting on the fence.