per-minute is really just a way to express the cost in a human friendly name. Doing per-hour, per-second, per-day could all result in the same total value just at a different number. If anything per-minute is better than per-hour as you won't be charge for minutes you don't use.
But why not make it "per GB Logs ingested" or "per triggered job" (or both)? These should reflect the points where GitHub also has costs - but not per minute.
the issue is it's per-$DURATION
it could be per-workflow, regardless of duration