Are you implying that the limited quantity is a bad thing? That's a good thing, because it means its value won't drop over time due to diluation, as happens with fiat currencies with no limit on how much is issued.
A limited quantity is a very bad thing for a currency. The value is _supposed_ to drop over time. That is the entire reason it works as currency. The only point of currency is to encourage and enable trade. So you can trade your extra sheep for ducks without having to hunt down someone who needs sheep and has extra ducks and can make the exchange right now. In order to do that, currency needs to actually be used and traded. Currency that is under someones bed rather than in circulation is not doing its job. If currency increased in value over time, people would hoard it rather than use it.. Note that I am talking about actually hoarding the paper bills or treasury notes (or electronic tokens) not holding wealth in investments or a bank account. money stored in a bank account is being used, as are investments.
Think about it this way, if there were a finite amount of currency, and the world population doubled then everyone would have half as much money in general. Now, things would also end up costing half as much because it still takes the same amount of human effort to create the same goods, but there just isn't enough money to go around to keep everyones pay at the same numerical level it was before. However, this introduces a perverse incentive to hold onto money rather than using it since the buying power of money will double every time the population does, it will outperform many investments, so rather than starting a company, or lending the money to someone that can use it, people will hoard it. It will no longer fufill its function as a currency.
And, while your currency devalues over time, that doesn't mean your worth does. If they redefined the gallon to be smaller you wouldn't suddenly have more milk in your fridge. A dollar is a unit to measure wealth, not wealth in and of itself.