Could you explain this? I think the CB system does not quite prevent money creation, it just makes it less transparent. Inventing a jargon to nice sounding words to hide the creation of money (yes I look at you "quantative easing") also does not help.
If govts wanted to limit their power to create money, they could have made some constitutional law or smth.
I feel the CB system is more an invention by the bank(er)s, than by govts. If you look at the timing and trickery involved in singing the CBs into law all over the world, you will see this is not something done with full governmental/public awareness and consent. To the contrary.
However, the growth of the country is very hard to measure (directly taking the growth of the GDP would not necessarily match it), so there is no consensus on what the inflation should be exactly, which gives the authority in charge of creating money some leeway on exactly how much money to create. If this authority was the government, it would be tempting to have the inflation be slightly higher than the country's growth, in order to "trick" people into believing that they got slightly richer and have them spend more. And this could work for some time, but at some point people would become wary of the government and as a result would spend less, slowing down the economy. So it becomes a game (in the sense of game theory) between the government and the consumers, and the solution is to have an independent entity in charge of money creation, so people can know with more certainty that the "right" amount of money is being created.
It seems to me it would be a lot more useful if we create money and the government spends it (e.g. on infrastructure, or by distributing it directly to people most likely to spend it), rather than indirectly creating it through QE (which in mechanism, if not in effect seems quite different from printing money), etc.