Essentially not a good idea.
Whispers just do not work for bots and should be avoided.
Then you end up with two notifications.
The one in public chat of the channel points being used.
Then you repeating that in a whisper
But the user is already on the channel as the only way to use points is via the “store” at the bottom of chat.
So your whisper is a double
Display the outcome in the extension of via Extension Chat.