In my state at least (New Jersey), you can't operate as a drug "counselor" without having a license.. and the license application requires you have certain education, training, and credentials.
I believe there are real legal consequences for falsely claiming to be a "licensed" counselor... or offering drug counseling if unlicensed. That's how the laws are written.. they make a law requiring licensing, and that law also sets the criteria for qualifying, the entity responsible for review and approving, and the consequences for breaking the law.
So really it is the licensed part that matters most.
There are a few different types of credentials for drug counselors like "Licensed Professional Counselor" (LPC) and "Licensed Clinical Counselor" (LCC) but unless they are LICENSED you probably don't know if you are safe/getting the best help.
Some credentials cover supervising other counselors, and some are specialized for business operations of counseling, while others specialize in working with the state and aid programs, while still others may be more medical vs. administrative or "clinical".