Doesn't have to be wireless, but a remote thermometer will buy you a couple of things.
1. What temp the meat is. If you don't have one, you have to open the door, stick the meat, wait, check the temp, close the door, let the unit come back up to temp. EVERY time you open the door to check, it let's heat out
If you're lookin'...you're not cookin'
2. If you have 2, you can monitor the smoker temp (what IS the real internal temp of the smoker).
After you get years of experience, take good notes and learn your cook times, you'll rely less on one, but having a temp probe is a very help thing to help you with the learning curve of a new smoker.
Someone did point out to me, the question was about AQ's. My response was more generic, to any smoker.
With an AQ, IF you're using the meat probe, it will give you temps of the meat and the LCD will tell you the smoker.
I WOULD verify all of them with an external thermometer occassionally.