That’s right. That’s why a blessing is distinct from an exorcism.
As for God being bound by an “arcane” ritual, that is only so because he himself has given the Church that power. We don’t bind God, but he has promised to honour what the Church has decreed according to the power he himself gave her.
If the exorcism is not done, it is not done. If the Rosary is blessed, it is blessed, but since there’s a St. Benedict medal, why would any knowledgeable priest omit the specific exorcism as well? A blessing is not an exorcism. A blessing sets aside an object as a sacred thing. An exorcism is a weapon against demons.
So simply put, if the priest says a blessing over the Rosary, the Rosary is blessed. But the medal is not exorcised. So again, why anyone would want to deprive himself of such a powerful weapon doesn’t make sense, since it’s there. And since the Catholic Church itself has given the rite to exorcise a medal, then by all means we should use it.