Even in cryptocurrency, I feel like the level of precision is mainly aspirational + cuz they can. Who cares about 1 wei in the context of a transaction that costs around 100 trillion wei on its own? The smallest unit of ether I've ever seen in any kind of UI is 1 gwei (1 billion wei).
Forgot to also add, cause various parts of a cryptocurrency ecosystem are much harder to change than traditional finance. So I can see why they throw in a ton of 0s and use 256-bit ints just in case.
