I think you mean GeneralizedNewtypeDeriving, not DerivingVia. GND lets you pull instances through a newtype, trivially. DerivingVia lets you define your instance in terms of an instance on another newtype.
Exactly. I intentionally avoid GND because it can be quite wonky, and DerivingVia basically subsumes it. You do still have to have slightly more explicit declarations of instances, but IMO it's worth it for the control.
