In general, I'd say limit how much your name is associated with crap. Corporate jobs have me making terrible stuff all the time, I just try to keep people from finding it through searches. The big deal is that when someone good does try to hire you, they don't want to see a previous work that is bad. Could a terrible band ruin a viewers enjoyment of a good music video, absolutely. Will people see your skill if you do a good job, yes. Would I film a porn and then show it to people because I got the lighting just right? No. I wouldn't film it at all. Talent aside, you don't want to really associate yourself with low quality people or products when you can help it.
If you need some money and experience, just use a pseudonym. If you can do better, do better.