Talking about atemi as a blow in the context of dojo practice is only creating more illusions. You can’t learn swimming in an empty pool. As in the dojo nobody really hits an attacker (as in boxing, kyokushin, MMA or MT), all these big talks about atemi it is exactly as you are trying to swim in an empty pool.
Of course, one could argue that attacker must react in ‘natural and safe way’ and if he is conditioned like that, we can hit for real.
Unfortunately, the objective definition of ‘natural and safe way’ simply doesn’t exist, and every instructor creates one for himself. As a result, his students will have certain particular conditioning that will be invalid in other dojo. I’ll not add that it will be not valid also on somebody outside of aikido – to not go off topic…
That’s why, IMO heavy use of atemi as a blow in the dojo as a key element of every technique it is only adding another illusion. The techniques become deformed by artificial reactions of attacker.
I believe that atemi in aikido has nothing to do with hitting, waiving, distracting etc…Atemi in aikido it is about stabbing with tanto, wakizashi or sword. It must be done in the position that attacker can’t avoid it. As that, we must practice empty hand techniques in the way, we don’t need to hit attacker. It is additional challenge, but only this way we will not fooling ourselves with illusions, we can preserve save practice in the dojo, we can develop perfect, clean techniques without any opening and after few years of such practice, one may discover where and how he can stab an attacker.