I'm confident they could add it but I'm a trust but verify guy. With all the outdoor cooking I do I have a third party monitor device (well, more than one).
Also; in my feeble mind it's my experience with my Traeger, RecTeq, and Weber pellet smokers that their temperature refresh rate is considerably delayed. I'm guessing when I say they don't necessarily want us to see the temp swings, which I understand are normal and appropriate. And whether right or wrong, I trust my third party units more than the thermometers of my smokers. If I had to rely on just one, I'd pick my Fireboard.