> Who would ever want this?
Anyone who wants to provide some level of flexibility but within bounds. Say, you want to allow <strong> and <em> in a forum post but not <script>. It's not too difficult to imagine uses.
Forums would already have code that sanitizes user input when it's submitted. Users aren't directly setting html elements.
Forums would already have code that sanitizes user input when it's submitted. Users aren't directly setting html elements.