Based on personal experience, I prefer the old fashion adapter with a wire. OBDII connected to USB port.
I bought an inexpensive WiFi OBDII adapter from Amazon. First thing which I noticed was that there were monitors just not available. With a wired connector, I was able to see transmission gear, transmission gear ratio, torque converter slip......not the end of the world. I could still monitor all the temps I wanted. I contacted the Amazon Marketplace seller. I also mentioned that the app was not able to connect to the car's computer in "key on, engine off". I had to start the car, then the app would connect and display information. Sometimes, that took a few minutes. Again, not the end of the world. They sent me a replacement. Same results. Replacement unit worked, or didn't work, exactly as the original unit. I contacted the seller again. The seller refunded the purchase. I now have 2 of these units, free after refund. But what good are they? I can use them for a basic connection to monitor my operating temperatures. Which is fine, and I do use them for that. But they are useless if I want to use Forscan for any programming. I just can't trust something like that. So stay away from the cheap stuff.