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.
No one can really know if for what reason bitcoin was produced, maybe it was created for criminal activities, or maybe it was created for something good, but once it is made it can be used for anything, now it depends on an individual if how he/she will use it because it can be used for either way.
If it was created for criminal activities then bitcoin will not be successful, the fact that we can trade it and it is increasing it's value it's not the major activities of criminal activities is the cause, it can be use for good and bad and will only depend on the users.