Yogis and fitness instructors I've spoken to see Gumroad as being too "techie" and the few that have tried it felt it was more geared towards selling online assets, rather than live classes.

For now it's very basic, but I'm working on a few features that are specifically geared to helping live class creators sell more easily, primarily calendar integration, support for multiple classes being sold, and support for monthly subscriptions to all classes from an instructor.