How do you feel about sperm banks?

I just watched a very interesting TED talk about how sperm donor conceived children and legal parents felt later on about the choice. I then looked at the comments section and was surprised how controversial it was to many people. I personally view it as a safe and easy way for couples who aren't able to conceive to have a child or for a person who doesn't want to have a relationship to have a child (in fact I'm considering doing this way years from now), just like a surrogate mother would be.