Also, it's easier to learn in a progression than to go back and learn the fundamentals, which is probably the biggest indictment against fast learning for anything where your eventual goal is to be highly competent or mastery.
Here's a bit of my real-world experience. I've been told countless times by managers that "we just want to hire someone good; I don't care how well they know language XYZ". Then, the majority of the people we hire who don't have expertise in that language never go back and do the work to truly learn it from the foundations. It's not just programming languages, but other subjects as well. In general, people rely too much on google or StackOverflow to bail them out, when they get into trouble, but that will barely get you by and never result in excellence.I don't see the OP suggesting that he is not going to dive in deeper, so I don't see a good reason to presumptively jump to the assumption that this speed learning post suggests detailed aspects are not important.