Pure capsaicin in it's powder form is considered a toxic substance. It ships with full MSDS high risk packaging and labeling as a toxin. It can cause severe burning and discomfort on the skin, it's an irritant when inhaled, and if injested straight, it can cause severe intestinal discomfort. I don't know if it's ever caused death, but I could see some very severe problems if it's not handled correctly and handled with extreme caution and physical protection.
Capsaicin powder is meant to be used in other applications, not to be injested straight. It's used in pesticides/animal repellants, law enforcement pepper sprays, and other non-culinary uses. It does have it's uses, but it must be handled using extreme caution. If a person doen't know what they're dealing with or how to use it, they should just leave it alone. It's not something to (bleep) with.
When diluted to a proper level and in the proper medium, capsaicin powder no more or less dangerous than any superhot chile. Superhots can be dangerous and cause severe discoumfort, etc. also. Is one worse than the other? I don't know. It all depends on the application, the chile, how much was injested, how much was on the skin....too many variables to say. jmho-