I understand that Shinobu Kocho techniques are designed to inject large portions of Wisteria poison in the demons to kill them, so maybe other demon slayers couldn't kill demons this way. Nevertheless, they could use wisteria poison in the swords to at least weaken the demons when they are fighting them, if they can't kill them.
Why do demon slayers other than Shinobu Kocho not use Wisteria in their swords to inject poison in the demons to weaken them?