This kind of content is usually shared by people who are learning a language out of genuine interest for the first time. Most of the time it's Japanese because of the popularity manga and anime enjoy, and the challenge of learning a language that's so different from one's mother tongue. There are countless blog posts written by people to whom it "clicks" for the first time, and they excitedly run to their computer to share their novel experience. I don't see anything wrong with this, let them enjoy the moment. But if they stick to their learning routine, they will inevitably learn the truth that is that the only way to learn a language is to interact with it a lot through all possible channels - speaking, listening, reading, writing. Mnemonics may work for some time, but in the end one won't be able to actually use the language if they don't learn it intuitively. And there is also the fact that most of those people live in places where Japanese is not in everyday use, limiting their opportunities to practice it.