He gave desperate people hope. For a clue to what the Germans saw in him (and themselves) watch Triumph of the Will.
you also have to look at the state of Germany at the time he originally came to power. Germany was experiencing some rather severe economic dislocation. Hyperinflation was rampant. Several years ago I bought a 50 Million Mark note. When it was printed, it wouldn't have bought a loaf of bread. In dire circumstances, people do insane things.
I used to not be able to understand how people could support his genocidal regime. In the past several years though, I can see how it happened. There are sheep everywhere who will be led anywhere they are told to go.