I'm working on a hypothesis that the 'blocking' movements weren't actually meant to be block punches and kicks but as close quarters grappling techniques.
Blocking was always designed to block an incoming strike. But the mindset of a traditional block wasn't to just block, but punish. For example, I'm blocking a punch, but in my mind I'm STRIKING an incoming punch with my Forearm. My opponent was kind enough to give me their arm (as a punch) so I should be kind enough to damage that arm in return. This is the most basic concept of blocking. You may hear people say that they don't block, but what they are describing is this mindset.
In a traditional sense blocking is never just blocking. Blocking is more like BLOCKING + DAMAGE OPPONENT or BLOCKING + FOLLOW WITH STRIKING OR GRAPPLING.
Also keep in mind that a BLOCKING MOTION may have multiple applications. This is when you start getting into hard and soft techniques. It's very rare that a martial art technique will have only one application for that motion.
For example, your video, how he shows blocking the front kick is exactly how Jow Ga Kung Fu uses that motion. It can be used to redirect or smash an opponents leg. There is a nerve that runs down the leg and that particular use of the technique that he was showing will strike that nerve on the leg. If it block misses the nerve then the secondary effect is redirection of the kick which allows you to enter (move forward), the third effect is bruising of the leg. It only works if the forearm is conditioned. The key to using this technique is that you must move off center of the kick, if you don't move off center then you'll risk hitting the shin bone and breaking your arm.
What I've noticed through my own learning of martial arts techniques, is that there is often a lot of figuring out to do. Some teachers will tell you exactly how some things work, some will choose not to, and some don't know at all. The only thing that is consistent is that Martial Arts takes a lot of exploration to really understand how the techniques work.