We think the dollar is safe, but history is full of hyperinflation disasters.
Germany (1923): The government printed money to pay war debts. Prices rose so fast that waiters stood on tables to announce new menu prices every 30 minutes. People burned cash for heat because it was cheaper than wood.
Zimbabwe (2008): They printed 100-trillion-dollar bills. You needed a wheelbarrow of cash just to buy bread. The currency eventually died completely.
Venezuela (Today): Inflation hit 1,000,000%. Being a millionaire meant you could buy a cup of coffee.
Hyperinflation happens when trust in the money breaks. Once it starts, it is almost impossible to stop.
Bitcoin is designed to never suffer this fate. Its inflation rate is hard-coded. It goes down every 4 years (the Halving) until it reaches zero. It cannot be hyper-inflated by a desperate dictator.