1)
Why do they make these known?
1.
Radak: Just like they bless and thank among themselves, they must inform people who do not know.
2.
Malbim: Really, man cannot fathom or tell Hashem's Gevurah and praise - "Mi Yemalel Gevuras Hashem" (106:2)! They do so only to inform others. They cannot tell the Gevuros themselves (Elokus), just what people perceive - overriding nature.
