Not a scientist but I learned those two concept from following the question of 'what the hell is a causality?' and reading related articles. My tentative conclusion is that we still haven't figure it out what causality is, and the main question mark is the emergence and downward causation. Granger causality is just a cool technique to infer causality from correlation, directly contradicting the mantra 'correlation is not causation'. They are just saying they also developed a cool technique to infer causality from data.
We know what causality is. A fully formal definition that encompasses all human intuition for causality isn't fully realized yet, but we know in general what causation is and we have been doing science to establish causation for a while now.
Granger causality is not actually causality. A time delay is required for cause and effect, but a correlation between two events can have a time delay as well.
Therefore seeing a delay between two events does not mean the first event caused the second event. But establishing causation between two events does mean that there is a time delay between the first and second event.
Causative experiments are much more rigorous then relying on the existence of time delay to establish causation. Medicine for example does not rely on granger causality.
