This is key, because a hallmark of product announcements has always been live demos. It's a simple fact that live demos of features are far more impressive than pre-rendered demos. With live demos you can see something working, and you know there is always the risk of a feature not working (like say Face Unlock during Google's Android 4.0 Ice Cream Sandwich announcement).
So far, all we've seen from Samsung are videos of features, and one skit where it could potentially have been a live demo (S Translator). The host has even gone out of his way to make jokes about how all of these people are actors and what they're doing is fake. And, overall it's looking like Samsung has the event 100% scripted. Is that a mistake?
We're not sure, but at the very least, it makes for an awkward announcement. Especially since it seems so clearly built to be a live event experience, but the livestream doesn't have the audience on mic, so it sounds like every joke and big reveal are falling flat to those of us watching from home.