Transforms into: A detective that also happens to be a car

Why is he useless?

Criminal No. 1: Hey, I think we should stop talking about our secret plans.

Criminal No. 2: Why's that?

Criminal No. 1: I think we're being followed by the Enormous Transforming Robot Detective.

Criminal No. 2: You mean that Honda wearing a trench coat and reading the newspaper?

Criminal No. 1: [pause] Yes. That's exactly what I mean.

Private detectives rely on being able to blend in and remain incognito while spying on suspects. Leave the huge, shape-shifting robot monster at home for this one.