It got really popular because a lot of people want that. Typing is cheap. If a bit of boilerplate and a couple of files drastically affect your productivity, you're not solving a hard problem (and if you're not solving a hard problem, which is the common case, there are a lot of other tools better suited for it).
But because it got popular, everyone jumped on the wagon, including people who were not the target audience, or were not solving problems it was a good tool for. Now, people try to force Redux into being something else, and it really, REALLY sucks at that.