So long as you're ok with your coins getting mixed with (and thus providing cover for) the more criminal stuff, I guess.
There is the concern that you'll end up with Bitcoin that's been tainted in one way or another. However, at least some mixing services get coin from miners, so it's clean. And you can check for that in the blockchain.
That's mostly a concern when you're mixing Bitcoin before converting it to meatspace fiat. If you're anonymizing Bitcoin purchased with meatspace fiat, it doesn't matter so much if some is tainted. Or at least, it won't unless tainted coin gets blacklisted.
Just a thought