Very interesting. I see they are selling a vaporizer for pot. Sounds like a lot less trouble than a hookah. That paraquat sounds bad though.
Yes, asthma can be effectively treated with marijuana. This is known throughout the world, except in a little village in Somalia where a witch-doctor named Ogka-Mogulu runs the clinic, and in the Washington offices of the Drug Enforcement Administration. Before marijuana was made illegal marijuana cigarettes were sold specifically for the purpose of treating asthma. That being said, most of the "street" weed sold is contaminated by various substances, Paraquat, being the main problem, a powerful neurotoxin used by the DEA to spray the plants in the field. In addition there are the legal aspects of the use of the plant, which in some jurisdictions are quite serious.
My son suggeted a hookah (which I used). It is also called a nargile or a hubble-bubble. In this way the tobacco/marijuana mix is filtered through water so most of the undesirable stuff you don't get (no smoke or tars, for instance). Also he said not to inhale, that the marijuana would then be absorbed through the mucuous membranes. Lots of people in the Middle East and India smoke tobacco with a hookah. Unfortunately I don't like the smell of marijuana and don't understand why it would be used recreationally. It makes you a little leaden. I was at a party many years ago with a lot of people I did business with. Everyone seem a little slow on the uptake and sort of dumb, which I didn't understand since I knew them. I was later told that everyone was smoking pot.
I have a cousin who used it for her tremendous heart pain. Like you said only for when really needed. The only thing I would be wary of, is just like cigargettes you are also inhaling tons of toxic chemicals into your lungs, which is just as damaging. And considering you already have COPD I would be very careful with how many you smoke.
As a postscript to the above, I do not have an addictive personality and would only use marijuana if I were having a bad day. That is, if it is safe.