Have you ever thought would happen all of your friends and fans on Facebook if it folded up tomorrow?
They would simply disappear. Facebook wouldn't even need to fold for this to happen. They could close your account for violating some new terms and conditions. In the future, Facebook may even ban pages it perceives as business related or move them to a new business related social media network.
That is why you need your own business website which you can control and will continue as long as you maintain it.
Do you need your own business website even though you can use Facebook to communicate with your customers?
Absolutely. Facebook is something you do in addition to your your own website, not instead of. Most of the Internet is not on Facebook. It's big within some circles, but most people, and most of your own website's visitors do not (and probably never will) use Facebook. Not everyone on Facebook is as active on it as you are. Just look at your own Facebook page and you will see that it is the same small band of people posting on a regular basis.
Facebook is like "preaching to the converted" and will not attract many new customers. New customers should be converted by your own website and then directed your Facebook page if they are a Facebook user. And remember, most of them probably are not!