In real history, is the deathless gold medal really useful?

After Liu Bang established the Han Dynasty, in order to consolidate his political power and gather heroes, he invented the Danshu iron coupon as a reward, which is commonly known as the death-free gold medal in later generations.

However, five years later, Han Xin, Liu Bang did not let him go because of this deathless gold medal, but directly killed him, not only that, other heroes also died one after another, and finally of the 8 kings he was given, only Wu Rui, the least powerful king of Changsha, survived; Sima Qian also made statistics on this, and more than 100 people were rewarded in the early Han Dynasty, and finally only 5 people were left alive.

In the Ming Dynasty, the founding emperor Zhu Yuanzhang also issued a death-free iron coupon to the minister, as the highest reward, if the minister broke the law, as long as he took out this, he could avoid death, and this iron coupon could also be passed on to future generations. However, only 10 years later, the Hu Weiyong case and the Blue Jade case broke out one after another, and almost all of the 34 founding heroes who had obtained the death-free iron coupon were implicated and executed.

Although the gold medal for avoiding death is a contract between the emperor and the heroes, but the leader of this contract is the emperor, and the final interpretation power is also on the emperor, although it is often the meritorious ministers who can get this honor, but sometimes the merit is high, but it makes the emperor headache, and from the historical records, we can see that most of the people who get the gold medal for the exemption from death will not have a good end, so it is also jokingly called the death charm.