99% of those who say they will get Fiat with their crypto are lying because they can't do it. How many easy cryto fiat exchange are there after 1000 have promised that. just look at allt he ICO say they will have you know it's a scam.
As far Im aware, all such cryptos claiming to do so only played on reducing or increasing inflation speed to some extent (while most of them just state it because it has a fixed maximum amount that can be created). Not decreasing total coin supply (or doing it in a centralized way which is like playing the role of a central bank). You effectively have fiat with
https://tether.to, only as long one of their banks dont go bankrupt (in which case their value drop down to almost 0) or the banking system of your country crash (which is why Zimbabwean can enjoy the rate of 1ᴜꜱᴅᴛ for 1.5 ᴜꜱᴅ due to black market fees for sending money out of the country for escaping capital controls).
The aim is to fully apply all parts of
https://en.wikipedia.org/wiki/Quantity_theory_of_money which is definitely not scam but the basis of modern (post 70s) economics theories. Decreasing the amount of coins available more than demand decrease must increase value since
https://en.wikipedia.org/wiki/Quantity_theory_of_money is scientifically true.
On the other side, like I stated previously, initial supply (pre-mined coin) shouldnt be too excessive, but rather match capitalization that a new crytocurrency typically gets at the beginning (around 20$) in order to get an exchange rate that can match the target in a reasonable amount of time.