I don’t disagree with you.
However, marijuana is currently still considered a Schedule I drug, federally. Form 4473, as you mentioned, does ask “Are you an unlawful user…?”. The question is then followed by this message:
“Warning: The use or possession of marijuana remains unlawful under Federal law regardless of whether it has been legalized or decriminalized for medical or recreational purposes in the state where you reside.”
The chance that you’d be taken to jail on the sole basis of carrying a firearm while also in possession (“possession” in this proposed scenario would also be debatable) of marijuana are low, I agree, unless there was some other undisclosed factor to the cause or circumstance of being involved in the law enforcement interaction.
Is it an immediate “go directly to jail” card? Unlikely
Would or could the driver (firearm carrier) be at risk? Yes
Are there risks, other than criminal? Possibly (could the CCW be revoked?)
There are and have been cases around the country involving CCWs, firearm purchases, possession that involve marijuana, both for medical and for recreation purposes. The rulings have been a bit all over the place. Some contested and overturned, others not. If or until marijuana is federally re-classified or decriminalized, there will remain some level of risk when a firearm and marijuana are in some way “connected”.
If I were a user, lived with, travelled with, directly associated with someone who was (or in possession of), I would take the necessary steps to mitigate that risk. For me, that would include not allowing a vehicle passenger to bring their marijuana. Again, for me, it’s just not worth the potential risk.
On the other question, I live in Florida, it has been decriminalized for medicinal purposes, but not for recreation. I am also not a user and wouldn’t be even if it were 100% legal.