I do not agree with you. Even i can you are completely wrong about it.
In my forum and portal: https:www.planetdp.org i had some experiences and user claims thatswhy i opened it this report. Maybe more than 30-40 users asked me that we can add other user as mention but we don't have inline notification. Somebody advised me that chat module :
mention and inline notification is working on it. People told me so. That means much more integrated with ipb than yours. I have bought it in a few days i will test it.
Actually even i should not explain you why should be some options of ipb as inline notification or some others. Because this is chat module under ipboard. How much integrated with ipb' options as much as good.
Also i agree with users. Because i missed many chat messages and then sent me pm did not you see the my message? But if i see mention of inline notification somethings there , i would not miss it. Yes some times i also thought about that.
Other chat app is really very good. But what i did not like : it is ajax. And yours using port. Thatswhy i preferred your babble. But in the same time i expect much more integration with ipb.
So it is up to you and your choice.