Home-assistant_v2.db grows, despite setting up InfluxDB

Configuration
3

I have set influx thus:

#### Database
influxdb:
  host: 192.168.1.4

…and set up purge like this:

# Enable recorder and set days to purge DB
recorder:
  purge_interval: 1
  purge_keep_days: 1

-But i thought the whole reason for setting up an external database was (amongst other things) not to fill the SD-card on my Pi3/Hass.io installation with the native database?