I don't usually buy drugs but if you wish why not. It's safer anyway than buying on the streets from criminals
Yes while its anonymous and simple to buy drugs with bitcoins but I would never advice anyone to buy drugs with bitcoins. You can use a gun to protect your country while you can also use it to kill people. So why using btc for bad man ?
(
https://bitcoin.org/en/faq#is-bitcoin-anonymous) All transactions are public on the blockchain, so they can be traced. Even mixing services are of little value since there are companies devoted to tracing mixed Bitcoins (
https://www.elliptic.co/law-enforcement/)
Bitcoin is perfect for situations where traceability (and transparency somewhat) are desired, such as for business, dining out, swaps, etc.
See this page, especially the section about Bitcoin mixers, for more info about anonymity:
https://moneroforcash.com/monero-vs-dash-vs-zcash-vs-bitcoinmixers.php