My answer to What do people with online stores put as the business address?
Answer by Ken Larson:
A business address is necessary to register an enterprise with the State and with the IRS for tax purposes. Most of my small business clients with online stores use their home address for that purpose and claim the IRS allowed home office space tax deduction.
Larger firms with warehouses and a need for a physical presence to fulfill their orders cite that address.
SEO may may be effected to some degree demographically by lack of an address presence on the web, but not to a significant degree in my experience.