[ivanmontillam]

For JSON serialization, which doesn't support fixed-point precision it does.

Floating-point precision has too many gotchas for being suitable to store Decimal types, especially for the Currency use case.

[notpushkin]

Surely it does:

  {
    "price": {
      "amount": 1000,
      "decimal_places": 2,
      "currency": "USD"
    }
  }

[lxgr]

How is that better than {“amount”: “10.00”} (which also bypasses all potential floating point parsing issues that your or your counterparty’s JSON library might have)?

[jameshart]

It is explicit about the fact that that number of decimal places is part of the data.

The semantics for your string “10.00” are complex - is it considered equal to “10”? To “10.000”? To “10.001”?

A user interacting with an API that uses such a string might make all sorts of assumptions about what it supports.

A user interacting with an API that has an explicit decimal places concept is being told ‘decimals matter! They can vary! Here be dragons!’