It serves as both. It gives a clear understanding of your goals while letting you debate the hows and whys with opponents directly.

Only the Jew knew that by an able and persistent use of propaganda heaven itself can be presented to the people as if it were hell and, vice versa, the most miserable kind of life can be presented as if it were paradise. The Jew knew this and acted accordingly. But the German, or rather his Government, did not have the slightest suspicion of it. During the War the heaviest of penalties had to be paid for that ignorance.