It will drive up the price of the Yuan - that's what the grandparent said. I don't know where you're getting debasing from?
Separately the Chinese government recently allowed the Yuan to float more openly. That's had the effect of debasing it, but it wasn't a goal - the point is to allow it to float at a market price (partly to make it more viable as a reserve currency), but the government wants to prop up its value.
I believe the mistake is to think one can design a reserve currency. The dollar is the world's first reserve currency only because the Bretton Woods monetary system defined it as redeemable for 1/35 ounce of gold after World War II. When the Fed defaulted on its gold obligations in 1971, the world got a reserve "currency" -- before the world reserve asset was gold.
I don't think any government can create an irredeemable credit instrument and have it accepted as reserve currency. Even the dollar as reserve currency had to come in the back door.
Separately the Chinese government recently allowed the Yuan to float more openly. That's had the effect of debasing it, but it wasn't a goal - the point is to allow it to float at a market price (partly to make it more viable as a reserve currency), but the government wants to prop up its value.