To be fair, you're still pretty stupid if you bring open headphones to public areas. Especially noisy ones. Closed leak less noise and block a little. Good for not annoying the **** out of others. Even better, try IEMs.
They can block anywhere from 24-32db. That can reduce the sound of a motorcycle into an average conversation! No one can hear them either, unless you're listening at 85db+
There's a reason they're so popular.
If beats ever released an open headphone - the world as we know it surely would end (lol)