Waiting lists in chats? Seriously? I am not supposed to loose focus of the chat window? Holy cow.
Maybe the browser will stop the js running in that tab from sending the ping and their backend might lose track of you wanting to chat with them.
As a result, most organisations have either automatically or manually implemented procedures to cancel a chat after a set period of inactivity.
This may just be a gentle nudge to try to avoid that.
YOU want help, if you can't be bothered to sit attentively to receive it, why should I send you text messages?