I welcome the German pirates for several reasons:
- "the discussion it brought up is already very beneficial."
- they have a high turn out of former non-voters
- "harmless stupidity": The German pirates seem to be ambivalent as of now. For instance, they are the only left-wing party that's not in favor of female employee quotas (an idea so absurd, there's not even an english wikipedia entry http://de.wikipedia.org/wiki/Frauenquote). If they dig deeper into this populist lefty anti-authoritarian theme (as it seems to be the case) the first thing they will achieve is less votes for the other left-wing parties.
And personally, I think this would be a good thing (see "female employee quotas").