Obviously any kind of currency an be use for both good and bad. I don't know why are you asking these kinds of question. But for Bitcoin in particular it has no special features in which it can be advantageous for people who want to use it in good, But for Criminal it has features for security and anonymity. But yes it's how a person use his Bitcoin if it is good or bad.
Yeah I have the same opinion, I don't understand why people keep asking this, I mean anything can be used for any purposes and so does bitcoin. And the fact that bitcoin is being used for illegal activities is undeniable but that doesn't have anything to deal with its being used for good things. So yes the purposes of using bitcoin do include good ones.