You should always have your own company website. Some businesses use their Google My Business profile, Facebook page or other business review sites as a replacement for a website of their own. But this is not wise, for one simple reason: third-party sites are outside of your control.
If Facebook decides — however unjustly — to delete your Page, it could take weeks or months to appeal and get it back, if ever. An effective digital marketing strategy should include both your own website as well as business review sites.