This is the concept of decentralization

(Digital currencies rely on a decentralized network, which means they are not subject to the oversight of any central authority, such as central banks.)

Well, these currencies are something non-material and intangible, and there is no oversight on them from any authority. So, regarding the entity that issued this currency, what are its circumstances?

How did it create it, distribute it, and determine its price? Isn't it supposed that any currency has a stable value or even a variable one but is known? Are intangible or non-material digital currencies' values determined based on supply and demand?

Is it a commodity or a currency that I buy a commodity with?