That doesn't show strength at all. A piece of paper can bend further than that. What it shows is it's flexibility, which compared to glass, is pretty fantastic. But that photo is nothing more than fluff, because it's a property that will never be of use in a stiff form like a phone.
Well glass is a pretty strong material, one of the hardest materials there is, but it's more brittle than plastic. Honestly if they can get glass to be flexible like that without cracking, I think this will be a really resistant material. I've dropped my iphone on cement multiple times, face down about half of those occasions, and it hasn't shattered. The plastic back has cracked though. Now I'm not saying that the standard glass that is used on present iPhones is invincible, I've seen a few unlucky souls with shattered screens. But the fact is glass is much more resistant material than people expect, and with whatever manufacturing techniques they have added to these new panels, I think it will be at least more resistant than plastic to cracks.