This could theoretically extend to signing you in, although Samsung would likely want to implement depth sensing or a similar technology to prevent evildoers from cheating with photos.

There's no certainty that you'll ever see this in the Galaxy S9 or any future Samsung phone. It's just a patent filing, and that won't necessarily translate to a finished product. It's a simple-enough concept, though, and it could be extremely helpful if you're struggling to get into an online store or are worried that you've locked yourself out of your phone.