There is a fundamental drawback of open source cryptocurrencies: anyone can copy the code and make a new one
Actually, they can't.
They cannot copy that cryptocurrency's network effect.
That's been demonstrated by the last year of market trading;
- CINNI coin copied Blackcoin's code but crashed in value compared to Blackcoin
- lots of coins copied Bitcoin's code but never got anywhere near Bitcoin's marketcap
- lots of coints copied Litecoin's code but never got anywhere near Litcoin's marketcap