The difference is that "!1" is a literal string. Like "!help" is a literal string. You can only prepend "!" before a variable (%var), identifier ($me) or an operator (isin). Try the following examples:

//if (!1) { echo -a true $v1 } | else { echo -a false $v1 }
//if (!help == !help) { echo -a true $v1 } | else { echo -a false $v1 }
//if (!$true) { echo -a true $v1 } | else { echo -a false $v1 }
//if (!$true == $false) { echo -a true $v1 } | else { echo -a false $v1 }

Well. At least I won lunch.
Good philosophy, see good in bad, I like!