It’s an interesting question. My stepdaughter set up on Instagram for her art business, plus was managing her own website as well. She’s given away her website now. I was very much “but you NEED a website!” However, Insta is working well for her. So I’d say “it depends”; on what you are selling, and on your target market. If you’ve got traction on FB and you’re happy with your niche, that’s awesome. If you want to scale up your business and have more control, then you definitely need a website.