It should definitely be shown off as a feature - everyone has had that frustration when trying to put a screen protector on some device.
Also, they say it can be re-applied. So maybe demo putting it on one way and then moving it to another wall or flipping it the other way. And demo on a non-white surface. It looks kinda transparent in the video because it's being stuck on a white background.
Also, if you stick with the same girl (which I think is totally fine), you should have her wear a more professional outfit (not to sound sexist or anything). What's your biggest potential market? (offices i'm guessing?) You should have her match that - so for offices, maybe business slacks and a professional top. Right now she looks like a college student, which is fine if you're trying to cater for that market.
Just super simple - 400 pixel high, two column. Left column just bullet points of the benefits of the product, rigth column awesome picture of the product.
Then A/B test that thing 3 - 4 times.
once you've got your messaging confirmed, move to video - video is much more difficult to a/b test IMO due to production