What is this "Vo LTE" notification bar icon? This icon  started showing up in my Android notification bar last week. I think it was after I used the Google Drive app for the first time (I had never opened this app before and was just curious). 

Now the icon is there all the time, occupying valuable notification bar real estate – and not providing any useful information in return, as far as I can tell. 

What is this icon? What is it supposed to be telling me? 

Can I make it go away? If so, is there a reason not to?
VoLTE means Voice over LTE. The icon notifies you that you are now able to phone over LTE. This means, it's not necessary in order to make a phone call to switch back to 3G (You cannot phone over normal LTE).
In short it's new and better. As far as I can tell you could disable VoLTE altogether, but I recommend you to simply live with it.