Not true at all. Most pill-dopers have little interest in pot. The whole reason they ended up on pills is Pot is stinky, bulky and easily detected by parents.
Also - once an addict is in the criminal/probabtion/parole system - they are unable to use Marijuana - this makes it more likely they will re-lapse to pills - for the same reasons as above - plus THC stays in your system for a long time - making it more detectable.
The idea is allow these addicts to use pot to address any cravings for opiates. A few puffs of weed can prevent an addict from relapsing and using opiates again. Yes - it’s a crutch. We used to use Methadone for this purpose. But that’s too much like treating a whisky drunk with beer.
Don’t see it in my experience. Most opiate users are free range when it comes to marijuana. Legal and illegal users. Most also use ETHOH.
I understand the concept, don’t see the benefit in practice. Too many different receptors involved.