If you have a local business you want to show up in Google, Yahoo, and Bing. If you have a restaurant or any brick and mortar shop where your clients come in then you want to work on your localization & maps optimization.
Google, Yahoo, and Bing maps optimization and marketing will help your business be visible to your customers when they are looking for a product or service you offer.
If your business survives by money spent by local consumers, then maps optimization should be a critical component of building your business, online and offline.