I’ve found a pretty simple starting point for
testing the bones of a website by using the
following single line of CSS:
border: 2px dotted black;
A poem might be a good example of something else you'd want to preformat.
Also, <pre> is a block element, while <code> is not.
The real issue is that there's something to be said about suggesting to write <pre class="code"> and <pre class="poem"> etc., or for that matter <pre type="whatever"> or simply <div class="whatever">. The real wtf here is that <code> has a special status in html while <poem> and other things that might want to be preformatted don't have their own tag. And that <pre> merely is a special type of <div> with some styling (which suits code just fine, but not poems) attached to it.