Being lightweight and not very intimidating in general (or good in any sort of combat) is a setback if you're gonna be an aspiring criminal/kidnapper, it doesn't really do much for you in that regard. You've got to think strategically. You can look bigger and rely on the effect of surprise by wearing scary wolf pajamas in the image of a known villain on the loose. Impersonating the crazy evil wolf is convenient, you can blame all your crimes on him/her; bonus points if you go on a rampage at the same time. Police can't be on two spots at the same time! Not to mention it would make it a lot more difficult for identification in the event of a witness, or a CCTV camera catching you on tape. Make escape from dead ends by keeping your normal clothes in a handy backpack so you can change back into your regular self in just a few minutes. Foolproof!