This is an API for very small datasets (daily time series data). The goal should be accessibility and readability over saving a few bytes.
I'm not saying it's ideal, I just think the snark is unwarranted considering how common it is. I just checked InfluxDB and they follow a similar model (even more verbose). https://docs.influxdata.com/influxdb/v1.2/guides/querying_da...
Checked a few more and I believe they're the same - Microsoft IoT, Predix (GE), etc.