Well, again, there's a major difference involved in the inhale itself. MJ gets deeply inhaled, usually every time, and usually held for a few seconds, or more, to get the maximum effect. Unfortunately that leaves the smoke, and all its' byproducts way down in the lungs which, I suspect is significantly more damaging than a quick inhale/exhale, that is relatively shallow. The number of chemicals in a cigarette are mind boggling, let alone the number of byproducts they create but no one, at least so far or that I have seen, has analyzed MJ smoke tosee what's actually in there. I can guess "tar" for one thing and getting that way down in the lungs can'e be a good thing.
Anecdotally, a friends son has been "using" since his teens a few a day. He's now in his fifties and wheezes worse than I did before I started vaping. He's never smoked a regular cigarette to my knowledge. Granted, one anecdotal case, but I do believe it is indicative of what regular, long term, effects can be whether it's MJ or BT. Tar is tar.
I'm with you, Tibs. I don't need MJ to help me sleep and that's all it did for me both times I "experimented". Like everything, though, it effects everyone differently I guess.