I wouldn't say that. I have a Pro 780 and the ambient probe is off by 20 to 70 degrees depending on my set temp (20 at low temp and 70 at high temp). I use a Fire Board II for both my ambient and meat probe (I don't even know where the Traeger meat probe is since I've never used it).
With the WiFi capability I can still adjust my pit temp up or down until my Fire Board probe shows target temp. You're using the grill WiFi
capability, just not the ambient probe for data. Basically, I don't care if my Traeger probe shows 240, as long as the FireBoard reads 225.
You can also go to warming mode (useful if you're at temp and can't run out to the grill right away), shutdown, etc. The Pro series also has a better controller than the other grills, as well.
As others said, get a good instant read, as well. And always cook to temp not time. Your ribs will be much better next time, guaranteed.
Everything takes time to learn. I just got an OONI outdoor pizza oven a few weeks ago and threw away the 1st 4 pizzas. Pizza went into the trash and we went to Old Chicago!