How terrifying is the devaluation of Iran's currency (Rial)?

2022: approximately 1 USD ≈ 427,000 Rials
End of 2025: approximately 1 USD ≈ 1,420,000 Rials
Early 2026: approximately 1 USD ≈ 1,400,000–1,500,000 Rials
In just over three years, it has devalued by about 4 times.
Now, 1 million Rials ≈ 0.6 USD,
Almost at the level of worthless paper.
And if we look further back, in 1979,
1 USD ≈ 70 Rials.
In less than fifty years, Iran's currency has devalued by over 99.99%.
Do you know why this is?
This is a warning sign.