You can't contact your customers via email through Udemy. My customers are my audience and having an email list is crucial. After I found Gumroad, it was a no-b

You can't contact your customers via email through Udemy. My customers are my audience and having an email list is crucial. After I found Gumroad, it was a no-brainer to use their platform. The course site is basically just a marketing page. There's information about the course, some blog posts, and the ability to pay. That's it. The biggest advantage of Udemy is its audience. How much are you willing to sacrifice for using Udemy to gain an audience? I'd argue you should build the audience first, then sell the product.