A missed opportunity with Astarion - eviltoast

I feel like an oversight or a missed opportunity regarding Astarion was that he couldn’t perform Vampire Bite on Cazador during the Ascension ritual fight. Like I understand that you can’t use it on undead but with the trouble that the game established with Astarion explaining how a vampire spawn can turn into a true vampire, you would think that biting Cazador would be an exception. I think it would’ve been a great and ironic twist for Astarion to be able to become his own master that way as well. But oh well, I’m guessing it would’ve lessen the impact of certain outcomes to Astarion’s questline.