This video just just has music playing in the background. It doesn’t matter in my opinion, he is just showing you the technique.
The pins of the finger joint are 10 mm ( 0.3937 inches ), the diameter of the axle is 2 mm ( 0.0787 inches ). This box would make a great small gift. Once you have done one of these hinges, it isn’t difficult at all. Of course there are many projects in which you could use a hinge like this or a variation of it. I would recommend using a hardwood when you make a wood hinge. Hardwood hinges are just going to age better than a softwood ones.