Not as simple as that. Currency debasement is simply the lowering of the value of a currency. Inflation could either be monetary/currency inflation, or price inflation of goods and services.
Currency debasement is a problem while currency inflation is not necessarily a problem if demand for the currency is stronger than its supply. Basically if you are running your economy well, making it more attractive, producing high quality goods and services, there are strong demand for what you produce, etc. demand would be so strong that you could inflate or print out more money to certain level, maybe 50% lower than the demand for the currency yet the currency would still increase in value. The demand for the currency have become extremely high in this regards.
But if the supply of a currency is greater than its demand, price of goods and services would typically rise when the currency is used to increase spending of the goods and services thereby increasing their demands, and if their supply is not increased enough.
So it basically depends on who runs the economy, and how much influence he/she has. If he knows what he is doing the currency and price of goods and services will be OK or even be better regardless of inflating or increasing the supply of the currency. In this case, the currency won't be debased
*A currency could also be inflated in a controlled manner by competent people and used productively, yet it won't be debased nor price of goods and services increased.

In regards to Bitcoin, having 21million supply cut isn't enough if you don't have the right people to make it valuable and increase its demand. So, it could still lose alot of its value and its price will fall in a short period of time, if it's being mismanaged, misused, not properly developed  etc by the wrong people.
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