We've spent over a year building this product and about a month creating the content. Now we're giving it all away for free. I think it's fair that we ask people to authenticate.
I was going to check this out, but couldn't find a privacy policy or other statement re what you might do with harvested email addresses. https://github.com/scrimba/community/blob/master/TERMS.md seemed like the obvious place to look. I'm not remotely anticipating anything malign, but clarity of intent is important.
One nit: I like listening to tutorials at more than 1x playback speed, and I was overjoyed that you added the feature but it’s not persisted between videos which is a bit annoying. But other than that This product is amazing!