If you read what I said, I said that strikethrough is used to cross out something that is incorrect without removing it. This is useful on forums when someone has already replied to something you said and you realize that what you said was wrong. You can cross it out so people reading it after can know that it's wrong without removing it, which would make it look strange when the post that replied to you quoted your mistake.
Because you cannot edit previous lines in a channel or query, this is not useful in the same way that it is in locations where it is used.
