Nowadays, everyone is online. Whether you do business online or not, your customers are looking (searching) for you there. They want to know as much about you and their potential experience as possible before they walk in your door or pick up the phone. They want to interact with you via social media or email or another platform. Your customers are also looking for information, sometimes even from the front door or parking lot of your shop. If you don't provide that information, it will come from either generic search results or your competitor.
If you create a strong website that provides information about your business and your industry at large, you'll gain greater access to your audience and the ability to communicate with them directly. Your website should educate your clients about the experience they will have with you and the products and services that you offer. Whether you sell online or not, a website is always an opportunity for education.