No. That what happens when buy a course from someone who doesn’t know how use Gumroad’s features to host courses properly.

Gumroad TODAY allows creators to set up their videos in a streaming, course fashion without having to download any zip files.

If you upload the videos directly without being zipped, they can be streamed directly from Gumroad via the browser or mobile app.

Gumroad has a simplicity to it that overrides the cons of Teachable that you mentioned. It has an internal marketplace but maybe not as robust as Udemy or Teachable. But it’s still a good choice.