Reader-created confusion? As opposed to...?
Writer-created confusion, meaning confusion which arises due to the words present or not present - a distinctly different thing from confusions which arises despite all the necessary words and context needed to receive a clear message.
In most cases, if two different people can read something and one can understand precisely what the author intended to be understood, and another is confused, it's because the second reader has created their own confusion (likely by skipping words present, inserting words not present into the writing as they think are needed, or by not knowing what a word means even though it is used in its most common meaning and context) - not because the first reader is some kind of lucky guesser or mind-reader that can arrive at the proper understanding for some reason besides that it is what is said on the page.
If all scrolls were spell scrolls, so "scroll" would mean one thing and one thing only, that would remove a lot of reader-created confusion, since many players automatically think of "things with spells on them" when they read about scrolls.
Yes, if there were no category of item to cover any and every magical sheet of paper/parchment/vellum/etc. with writing upon it that when properly read has some special effect, and instead were just a single item type, it would be easier for these close-minded players to not confuse themselves.
Wouldn't it be better to write things that doesn't confuse the readers?
In some instances, yes. In this specific instance, most certainly not. What you propose when suggesting that the only magical scrolls be the singular type that cast actual spells is the equivalent of suggesting that we strip the variety of magical weapons present in the game down to a singular type (
vicious weapons, as an example) for no reason beyond that then it would be even more readily apparent what possibilities there are for a magic item that fits within the outlined category of magical item.
