I use the Sigma for cadence because the Garmin 200 doesn’t have sensors for that. I do use my commute as a training ride too, so have speed & cadence is useful. The Sigma also functions as an odometer for total distance records.

It’s also good to have backup system for distance & speed in case I forget to charge the Garmin, but this is not really necessary for a commute .

I was thinking of upgrading to a better Garmin / Wahoo, to replace the 2 units with a single one, but this would probably weight more!