Yes this will work well, any lines not matched by the pattern will be skipped. This is probaby the way to go so long as you don't need the full log data saved.
The other option would be to match everything but remove unwanted matches or have them bypass the aggregator using the [metric filtering](https://github.com/influxdata/telegraf/blob/master/docs/CONFIGURATION.md#metric-filtering
) options. However, then you are restricted to less powerful glob patterns instead of regular expressions.