HOW MANY TIMES DO I HAVE TO YELL THIS?
??Of COURSE you shouldn't use floats internally (unless you are doing something trivial like adding up items in a shopping cart).
We are talking about the JSON-RPC api. Which is an api for communicating between bitcoin and other applications, in which all values are turned into strings.
So: what are the best practices in the banking world for representing monetary values in strings? As far as I can tell, the answer is "write them out as decimal values and convert them to Decimal() or integer as you read in or write out."
Which is exactly what Bitcoin does, and which is what I think we should recommend to people.