Balance training is widely used in parkour because of its many benefits: it improves balance of course, but also body coordination, strenght in the stabiliser muscles, it increases joints stability, etc… Outside of parkour, it’s a tool that’s still underestimated, which is a pity.
For beginners and people looking to get back in shape, it’s one of the easiest moves to start practicing: simply walk alongside a line on the ground. There is no risk at all, and you’ll get a good training. Over time, you’ll improve to scale up to rail balancing.
For people lacking the time to properly train in structured sessions (e.g. me) , you can also cumulate serious training time by balancing on lines on the ground while you walk. You don’t need more time in your day to do this. Walk at a fast pace, brace your core, and you’ll get good training sensations. It won’t be a rail balance session, but your next rail balance session will be that much easier.
The exercise in the featured video is an excellent example of Interstices Training: you can train during your normal day, without needing additional time that you have to dedicate to training. And yes, you can even train with a baby carrier on (in my experience, kids actually like it when you fight for balance and you shake them).