Yeah, it totally seems like a gimmick until you see it working. The key is getting the bran to layer in right, and you have to drain the liquid every couple days or it gets funky. My kitchen bucket never smells, which still surprises me.
My cousin in a tiny Brooklyn apartment swears by hers. I was skeptical about the whole no-rot thing, but the liquid fertilizer for houseplants is legit. You just gotta be strict about that daily drain.