They are serious business. They're not the internet

Controlling public perception and the flow of information, especially information to competitors or potential competitors, is vital to any business. Leaking art to either the public (unknowing or unwittingly) or to other companies (and even if they make games on a different genre/platform/planet than you, they have friends who work at your competition) can frequently lead to serious problems.

And, of course, you're demonstrating that you don't really give a shit about NDAs. Which doesn't reflect well on you.

Different circumstances could change the impact of showing it, but there is no time where breaking that NDA is going to really benefit you.