Makiwara training is often considered as a conditioning exercise which is incorrect. Of course, proper muscles tend to develop, but the main priority and necessity of makiwara practice is to hone proper technique. The timing (kime) and feeling one's punch should have can only be sufficiently practiced using a makiwara or other material that can be used to contact with a punch or kick. It is stupid to assume that makiwara practice is to gain bigger knuckles.
Makiwara is an traditional method to improve your technique. Bags etc were developed which we also use often in the Dojo. We use elastic cords, but Ishikawa sensei used to explain they used tubes of bycicle wheels for practice. Then there is tetsu geta (iron shoes). We also use weights, which is not on the video. However, it is good for practice nevertheless. What I'm trying to say in the video is that you have to realise that each method has its specific objective.
KIHON 基本