Nowadays, many people strive to conquer the heights of programming in one language or another. There are debates about which language is better, which is more productive, many developers and beginners focus on benchmarks and foam at the mouth to prove something to each other. This is so childish and so pointless!
Ask yourself the question, what will you create using this or that language? Do you have a startup idea? Can you create something new? Remake an existing one, but make it 10 times better?
If you are offered a job or take tests and interviews, you will be given technologies that you will be required to use. Business, money, and interests of managers who have never written code themselves will carry more weight than the results of your research and study of effective programming languages. This is the fucking reality of the industry today!
Therefore, you need to learn something else: physics, mathematics, chemistry, neurobiology, any natural science. This will give you the opportunity to write something in your favorite programming languages that someone else really needs. Not boring schedules and product lists, mailings and stores, fuck commerce.
Natural on, that's what should advance your programming knowledge!
I'm not sure if I understand your question, but if you are trying to build a solution, you will have to know the problem. I am writing said mailings, database, rest interfaces etc. for which Java and Spring boot is pretty useful. Some people might consider this antiquated. I also used python for data science stuff in the past. Neither would i like to have been using java back then, or python now. But in both cases i needed to know what i was building before i (or my employer) chose the technology to use.
If you are offered a position where you will have to use a technology for something you think its not a good fit for then run. Some people might even be more interested in you if you tell them as it makes you look more experienced. And you're right, it is usually not worth it to have religious wars over 0.xy percents of performance gain, as long as you're not trying to build a house with a screwdriver.
The only question was the title, and the content of their post was answering their own question.
This post is just a blog post.
The title could have been "Why knowledge of programming alone is not enough", without a question mark. I would have preferred that.