... I do seo for various clients, and like anything you need to sell yourself. Real estate agents drive around in fancy cars to help show a sign of professionalism and wealth to help close deals. Sure a beater will get them to work but it may not sell a house.
I have had local prospect clients want to come over to my house just so they can see the computer. New client prospects are constantly wowed when they see photos of it.
Bottom line, not only is it functional, its a marketing tool, and helps sell my business. The computer has paid for itself in new deals. That alone is worth the investment.