Problem is that code is written by many people, so you have to agree on a way to divide (for example). Then, it means that you have to enforce the way you code it and current standard programming languages (python, java, c,...) don't help you there.
We need a decimal format because people who read the code are sometimes not coders how know about the various tricks to pack decimals in uint64.
So, u64 is perfectly doable, sure, but it doesn't scale with the various types of people who write/read the code.
(same thing for floats : you can do money computations with them, but that'll work only if the people understand the trade offs of the representation; and believe me, they're not legions)
We need a decimal format because people who read the code are sometimes not coders how know about the various tricks to pack decimals in uint64.
So, u64 is perfectly doable, sure, but it doesn't scale with the various types of people who write/read the code.
(same thing for floats : you can do money computations with them, but that'll work only if the people understand the trade offs of the representation; and believe me, they're not legions)