The main issue with this splitter is like any other splitter - it has a fixed distance from the table. Since the saw blade is raised or lowered depending on what is being cut, the distance between the spiltter and blade will decrease or increase. Since the safest splitter is one that is closest to the blade as possible, when making shallow cuts this splitter will be less effective.
However, if this is used as a zero-clearance-insert with splitter for every common height setting (for example, 3 inserts for 1/4", 1/2" and 3/4" stock), this could provide better safety.
From the video, it doesn't seem like he is chamfering the edge of the splitter that is facing the blade. You should - it will prevent the wood from bumping into the splitter in case the wood gets even a little twisted after the saw blade.
Finally, making the splitter out of wood is probably prone to breaking the splitter. The kerf of the saw blade is narrow (even more so with a thin-kerf blade), and such a thin piece of wood is not strong. A piece of plastic or metal would probably be stronger, or maybe some high quality thin plywood (I'm not sure they even make plywood this thin though).