Well there's 28 days that it isn't shining (yes, sidreal days exist on the moon). But you also don't have Earth in view (ever). The Earth is also loud. Combine these two and you got a great place for radio astronomy.

The far side also has a lot more craters. There are also places in the poles that are always in darkness, but those aren't the best places for observatories.

Think about what you just said, in context of why one side is light and one is dark. Where does the light come from?