I think so.
For most questions, a "pre-emptive" canonical is overkill. I agree with Malco's comment: "Usually we wait until someone asks the question...and it will eventually become the dupe target."
But this question is somewhat unique, because it is highly unlikely that a player who misunderstands lands & mana would ever ask a question about the difference between them. Most players who misunderstand it do so because they don't know there is a difference.
So even though we might end up with a good, organic canonical answer, it will probably be an awkward question to use as a dupe target. For a beginner, it would be confusing to have your (hypothetical) question titled "Can I use the Forest from tapping Llanowar Elves in the same turn?" closed as a duplicate of "Do I have to take mana from my deck or hand when tapping a dual land?" There are many questions that could be closed as a dupe of this canonical, but it would make little sense to close them as duplicates of each other.
A good canonical for this topic introduces the concept behind the underlying misunderstanding, and then provides a central place to put amazing answers. And I think Zags' post is doing an excellent job of that.
For a similar case, consider the canonical stack and priority question. Somebody who understands the stack is unlikely to have questions about responding to instants, but somebody who doesn't understand the Shock/Giant Growth interaction will have no idea that the answer has to do with the stack.