Here is a good physical explanation of how the irimi works against the tantodori yokomenuchi attack. They call it ‘bursting’ but we call it irimi or ikkyo dosa. The atemi in the video is designed to break facial bones. In Aikido, we use a light atemi to just distract the aite in our practice because we aim to just immobilize an assailant without damaging him.

Another difference is that we seek to control the aite without losing him like in this video. Finally, there is a chance the defender in this video can take a snap kick to the groin. Perhaps if his irimi were more to the side it would be safer.