What you need is an iron that will stay at 700oF whatever you throw at it tip or workpiece related. That means power, lots of it. That doesn't come from USB.
Considering my current iron is a 50W Weller TCP, that can switch between soldering 0805 packages immediately followed by large tag terminal capacitors and ground planes without have to do anything, change any settings etc. You don't even have to change tip with the chisel.
Soldering irons also take a heavy battering when you use them as well. The above Weller is 20 years old and looks and works good as new. I really can't see that working for very long.
I just don't understand why the product exists really. If I was in the market you can pick up a whole Weller TCP station for less cash second hand. This is just a flashy toy.