I agree...This really is the only reason I can think of to use a ping. Why would you try and get someone's attention before or after you send them a message? What's the point if you're just going to be sending a message anyway?
If I don't respond to a message and someone pings me afterward to get my attention, they will get an earful. It reminds me of that one person everybody knows that annoys the he77 outta you with constant messages over and over. Then you get into the "Are you mad?" or "Did I do something?" conversation and I won't even get into that because I'm already mad just thinking about it.
Ping is useless IMO.