Every currency will be used for a mix of good and bad activities.
What's more important is how efficient the currency is at enabling those transactions, and how easy it is for enforcement agencies to do their job.
As one of my old bosses at Ripple used to say: “you want everybody - normal people, criminals - on the same phone network so you have one place to check. You don't criminals operating on a private network the regulators don't even know about.”
Bitcoin is used for good and bad transactions. But it's not very efficient at either.