It’s very hard to do tags in the physical world. You need to stick different colored post-its to things and do a full table scan (with your eyes) any time you want to process all docs of one tag. Or you cluster things together depending on similar colors.
Hierarchy is easy in the physical world.
But what is crazy is since the dawn of computing we can store data however we want and project it however we want…and yet we still use hierarchy for file storage…like we still just have a filing cabinet of manilla folders.
Are you asking me what is the best way to organize information, trees or tags?
Do you also want me to tell you what is the best way to foresee if a given program will halt?
The point is, bringing facile statements like "just make the right choice" adds nothing to the conversation. Some problems are hard and trying to short circuit the conversation saying that's easy just pick the right tool doesn't even apply here.
The point is that the question of selecting a tool is underspecified unless specific context (job) is given. It says nothing about how easy/hard it is. It is not always true (some tools are just better in any applicable domain) but in this case (hierarchy vs. tags) it is. It is not deep but it is not a truism either.
Hierarchy is easy in the physical world.
But what is crazy is since the dawn of computing we can store data however we want and project it however we want…and yet we still use hierarchy for file storage…like we still just have a filing cabinet of manilla folders.