Why did roman coins decrease in value during the A.D. 200's?

During the A.D. 200s, Roman coins decreased in value primarily due to rampant inflation caused by overproduction and debasement of currency. The Roman government began to mint more coins using cheaper metals, reducing the silver content in coins like the denarius. Additionally, economic instability, military expenditures, and political turmoil further eroded confidence in the currency, leading to decreased trust and value among the populace. This combination of factors resulted in a significant decline in the purchasing power of Roman coins during this period.