But I guess that's exactly the point, isn't it? The fact that Flask/Express are so bare bones, you end up learning a lot, so for learning purposes makes a lot of sense.
In my case, I want to have a good base knowledge before leaning on any kind of "magic". I got into Python with the MIT course on EDX and got bit by the programming bug. I decided to try and get into the web dev stack, so I started to dive into JS too. Now I want to start to build stuff, and the reason why I asked the question in my first post is because it may be easier to just go deep into one language (can't do web dev without JS), since I am so inexperienced.