Yes, it’s a feature supported by many VOIP clients, and this comments section is filled with UPnP apologists
And TURN is one of those relays.
(I host a STUN and TURN relay myself, because I had to for my personal VoIP server for enough people to be able to connect on it. Downside is more use of bandwidth.)
edit: replaced STUN with TURN where appropriate, I did confuse both as they were provided as a single package.
What's also true, and what I think the GP was trying to get at, is that STUN requires an external coordination server. UPnP (I think—I am far less familiar with it) does not, because in UPnP you're negotiating the holepunching with the local router directly, whereas STUN is sort of using a loophole.
(and it turns out that the server software that I use implements TURN and STUN in the same daemon)