It's historical data. There is zero reason to request it more than once a day, and the users of such data will be interested in wildly different filters or aggr

It's historical data. There is zero reason to request it more than once a day, and the users of such data will be interested in wildly different filters or aggregates over that data. If this were being used to get the current rates, then yes, it would be a terrible design choice. But there are other services for that. This one fits its typical use case.