I trafficked hundreds of pounds of cannabis at a time for a decade while it is illegal, the origin of this is for sure a mold test. A huge percentage of weed has spores on it and it was a requirement on purchasing large amounts to do sniff tests for mold. Small time dealers and weed people picked it up and are aping oenophiles but it is really important you learn how to identify mold on weed by smell, I still smell it in dispensaries and those are the bags I pass on.

edit to say it’s not to say there aren’t people who can learn a lot about weed with a trained nose, but these types of strains and rigidity with genetics didn’t come until long after we’ve been sniffing bags. The only thing most people can smell without training is mold though, I highly recommend you do this, no one wants moldy weed.