The Concordat was signed in July of 1933. That is after Hitler's appointment by Hindenburg (1/30/33), after the Reichstag Fire (2/27/33), and after the Ermächtigungsgesetz (enabling legislation) that gave Hitler dictatorial powers. Hitler had also already arrested opposition delegates. And Britain, France and Italy had already agreed to the Four-Power Pact with Germany in June.
That is not "tenuously in power".
Moreover, the concordat guaranteed freedom of religion to Catholics in Germany, including the Nazis not shutting down the parochial schools, in exchange for an agreement that Catholic clergy would refrain from politics and the dissolution of a Catholic political party. The so-called "great financial benefits"? -- the right to keep collecting the church tithes. Wow.
Of course the Nazis violated it almost before the ink was dry.
And that guarantee was at whose expense??? At the expense of other people's religion, their freedom and their lives??? Your prelates were willing to sell others down the pike so that they could continue on unmolested??? And you think that God was pleased with this sell-out???