I don't know, I didn't fully get the idea of stroke order. But from top to bottom and left to right does help shape your character.
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It's a hard question since I never thought about it. Some anwser suggest it's part of the standard. Eventually you will write the same character no matter how you write it, but to resolve any ambiguity, there has to be a standard way to write. And some suggest the correct stroke order can help you learn cursive.