You can with the built-in Protocol if you handle all currency types within your singular protocol implementation or double-dispatch out to another protocol for the specific currency type (which should be fine).
If you truly want to protocol dispatch over an instance binding (I.E. full match) then the built-in Protocol cannot do that but ProtocolEx can (and it can be faster than Elixir protocols as well). But I don’t recommend it until you actually Need proper match semantics.
