How do you avoid malicious users publishing your content public? Or is it just not an issue yet?
Yes, the model is far from being perfect, but it allows me to pay at least some of my bills. I'm always curious to learn how to improve it!
[1]: https://squidfunk.github.io/mkdocs-material/insiders/#terms
So as a user, you can start some work based on the insider version and be confident that you will be able to release your work even if the insider version never goes public for some reason, instead of relying on a promise that the code will be released in an open source license.
True, although just removing a couple of words from the MIT license would still be a very attractive and easy to use license. Examples of words you might remove: "sell" and "sublicense".