Yes, Bitcoin is used for drug trafficking, illegal gambling, money laundering and other criminal activity but I don't see how that is a bad thing for the average Bitcoin investor. The modern world has tried to stop all of these illegal activities for a very long time and they have had no success. Drugs are cheaper, more potent and more readily available than ever before. Illegal online gambling grows every year. Matter of fact, I don't believe they will ever stop the drug trade or illegal gambling. It is just a fact of life. I do not support or participate in any way with the illegal drug trade, gambling ,or money laundering but I think they provide a certain valuable level of support for cryptocurrencies. They allow that cryprocurrencies will never be completely devalued because they have the decentralized anonymous features that support such illegal activities.
I don't think that pornography is one of humanity's greatest achievements and I can't say that it contributes much to society as a whole. However, during the 1990s, the pornography industry was the number one industry that led to research and development in the internet and because of the support of the pornography industry, the internet grew by leaps and bounds. Pornography eventually alowed for the massive worldwide adoption of the internet. I think that without pornography the world would not have the internet as it is today.
Today the internet is not solely associated with the pornography industry. As such, I believe that in the near future cryptocurrencies will no longer be so strongly associated with illegal activities.