Cigarettes are stress-relieving at first but the after-effects suck. So we have enforced a system-wide smoking ban. Cigarettes are very stressful to the body, way more than the temporary sensation of "relief" from stress that they give initially. Especially the little alters feel the "fall-out", including rapid heartbeat and nausea, and maybe a "crash" feeling.
But we all seem to like cannabis. Vaporizing minimizes the "negative"/"disruptive" stimulation that can come from smoking/combusting it with a joint or a pipe, so we prefer to vaporize whenever possible. Vaporizing also minimizes burn-out sensations
Whether cannabis helps or hinders really depends on several variable factors. The strain, the time of day, the people who are around, the goals and expectations you have for yourself for the next few hours... for example, if we are on a heavily sedating strain, but we have to be alert/sociable, then it feels suboptimal to be high. But most of the time it is relaxing and relieves social/emotional pain (it is an analgesic). And if we take an uplifting/energizing strain, and have completed solid prep for what we are going to be doing while high, it can turn into a really positive, productive experience!
People with DID often have chronic negative emotions from living with the condition and everything that goes a long with it. I know I do. cannabis acts like a salve on the chronic emotional bruises that people with DID seem to carry, as per its anti-pain properties. When our pain is relieved, we get a sensation of being able to "sit fully upright", instead of bent over and straining like a plant with a bruised stem

Furthermore, for our system, DID has developed co-morbidly with disordered eating, and cannabis also helps to bring some calm, acceptance and appetite at meal times.
But too much of anything isn't good... if we are TOO relaxed, then learning is disrupted... and if you're just relaxed and not learning anything for too long, you're gonna get depressed and may feel lost.
(-Asc, -whelan)
D: And if any of us are feeling unsteady/overstimulated, it's generally a good idea not to smoke/vape cannabis at all. A nap or a bout of exercise is good instead.