My SmartApp is subscribing to device attributes. If you have a device attribute that is changing every 10 or 30 seconds, then the app will already forward each change in value to InfluxDB.
Soft-polling is only there to fill in the gaps for device attributes that change infrequently (relative to your charting periods), as you need two data points on a chart before Grafana will draw a line between them.
But yes, you could change the soft-polling interval down to once per minute if you really wanted. The only reason I can think of to do this would be if you are producing charts showing short periods of time (i.e. less than 10 mins) and you are plotting device attributes that are changing less frequently than this.
Note, I’ve started a new thread here to consolidate discussion about my InfluxDB Logger SmartApp: SmartThings Data Visualisation using InfluxDB and Grafana
HTH
z.