Great film, and that line makes perfect sense.
It's a restoration. The idea is to use as many of the original parts as possible. You clean, repair and do what you need to make them good again. That's what it's all about.
But this is Brakes!
If you're at all worried about the condition of your brake lines, fit new. Don't hope for the best. I'm going to clean the GSX hoses up and see how they look. They're old and, once fitted to the bike, will be checked under pressure. Any bulges or leaks and they're heading for the bin, but for now we work with what we've got.