This approach depends very much on culture. For example, US culture is very much, get to the point, start with the conclusion. German culture requires you to outline how you got to the conclusion.

Interesting book on this topic: The culture map, by Erin Meyer. (https://www.amazon.com/Culture-Map-INTL-ED-Decoding/dp/16103...)

It has a whole chapter on this topic: 3 - Why versus How, the art of persuasion in the multicultural world.