Interesting stuff. I need to analyze it and test it on a partner, but I'm going to experiment with it.
In Ashihara, this is one of the very few "traditional" techniques, which use is not immediatly plain to see. It may be considered a remnant of the roots in traditional karate, but the reason it has not been removed (only modified) is because it has a practical use that is central in Ashihara.
Application 5:
Opponent kicks right leg mae geri. Block with soto uke, while simultanously moving into forward and to the left (position 3). Grab opponents right arm (just over the elbow joint), and place your left arm in his neck - shuto can be used here. This is the start of mawashi uke. Rotate clockwise while pulling his elbow up and pushing his head down - since you have complete control of him, you can knee him in the gut/face. This will eventually result in maki komi nage (forward throw). If you don't let go of his right arm, he will hopefully end lying on his side, facing away from you. Keep control of the arm with your left hand, and stand over him in a kiba dachi, pushing your left knee down in his neck.
See the below video. You may not see it, but the mawashi uke appears in several parts of the kata to control the opponent. It's easiest to see at the very end, when that good-looking guy is thrown on the cobbles. Maybe I'll find a better example later on.
Osu!