Agree, except for you CAN overdose with opium.
I know because I have.
But it's usually more the case with oral consumption or poppy pod tea, where gauging the potency accurately is impossible.
With smoking you can at least titrate and stop whenever you feel like it gets too much.
I did specifically note that it was possible to OD on opium if taken orally. Poppy pod tea isn't quite the same deal. I understand that in a few cases, it was discovered that the pods used contained high levels of thebaine which is toxic.