Delete Preference List

Hmm.  It doesn't look like that exists for me either.  Let me see if it's hidden with a preference.  The good news is that we are looking to invest more in preference lists as part of a more robust preference management solution, so we can definitely look into making this easier.  

As long as I don't use it in the config, will it cause any problems?

That's correct! It shouldn't be a problem if you don't use it. Right now you can't delete preference lists but as John mentioned as we look to invest more into the preference center that will definitely be a consideration!