excellent, to commend, to be able to
哿 centers on being excellent or praiseworthy, with the idea of commending someone for their ability. The meaning 'to be able to' is a natural extension of having excellent capability.
哿 combines 加 (add, increase) and 可 (can, approve), likely suggesting the idea of adding approval or commendation. The exact historical development is uncertain, but the component combination fits the meaning of praising excellence.
The top component 加 means 'add', and the bottom 可 means 'can' or 'approve'. Picture someone adding their approval to a person's excellent work, commending them for being able to do it so well.
For カ, imagine a car (カ) that is so excellent it gets commended by everyone who sees it. The car's excellence makes it truly praiseworthy.