It is, of course, a personal choice. That there is a level of risk does not seem questionable. Look through the injury forums and you’ll find a number of cases where people fell asleep, or intentionally went to sleep while clamping/pumping/hanging/stretching, and had disastrous injuries. Sometimes they recover, sometimes they never do. Then there are also people who do it with no negative side effect.
Just as there are huge health risks to smoking, weighing 400 pounds, or driving after downing a case of beer. Hell, even if you don’t drive, drinking a case you risk waking up with a horrible, ugly girl. Or worse. Yet, there are people who do those things over and over and nothing horrible happens to them. And there is the irony of people who avoid anything risky, and bad things happen to them anyways.
Does that mean its a good idea to risk it? That’s up to you. Every decision is a risk/benefit analysis. The benefit is obviously being able to PE for many more hours than you could otherwise. The risk is that your dick becomes nothing more than a particularly odd looking body decoration. Is that risk/benefit cool with you? That is for you to decide.