In simple terms therefore DO NOT put money into any coin with more than 90,000,000 coins divisible to 8 decimal places (Quark, Dogecoin etc) unless you are a speculator playing the pump n dump market well as by definition its dead in the water.
Well put. doge coins in particular try to put 60 tons of dung in a 53 ton bag. The numbers CAN be stored internally with no loss of accuracy where they are stored as 64 bit fixed point numbers, but fall apart when you try to access them via the RPC interface.
One can increase the maximum number of coins if they are willing to decrease the number of decimal digits. Otherwise they might want to understand the RPC interface's use of doubles for generating the json response.
But, I suspect that most alt-coin makers don't really care what happens after the first month or two so this becomes irrelevant.