Thank you for the update, but does this mean that if I call
BNSendGameData(10, OR, "Hi I am inviting you for event 178 Throne of Thunder meta.")
The user receives
[Jeremybell whispers] Hi I am inviting you for event 178 Throne of Thunder meta.
or do I have to create an AddOn that listens to BN_CHAT_MSG_ADDON which has to "decode" the readable text and displays this in-line?
Yes, if you use BNSendGameData you will need an addon on the other side to “decode” it.
BNSendWhisper is throttled, similar to normal whispers. Basically this change makes Battle.net chat similar to WoW chat, which it wasn’t before.