My understanding is that CGMs shine at having a large volume of good data. You can see how your biometrics are trending over time much better than the <10/day readings someone with manual testing will receive.
It's both. The volume of data is helpful in making adjustments to insulin basal rates or dosing ratio. The instantaneous data is useful for making immediate decisions, either manually or automated, about insulin or sugar intake. Seeing a trend line can be much more useful than a single reading from finger stick too.
