They've got a pile of 3168s they want to get rid of or acquired for free/near free. There is no reason to buy that card new in 2020, it wasn't even a good option for the price when it launched in 2016. +10 is a touch over the full per unit price on bulk orders of the ax200 (I just bought a couple hundred recently) so they are saying they save nothing by keeping a 3168 on hand. WiFi cards have this happen a lot since they are one of the few things that are still modular in laptops and most people wouldn't even notice (well in this case they might since the 3168 is only 1x1 and the ax200 is 2x2).

That being said if you're planning on running Linux do know for the ax200 you'll want to be on/backported from 5.4+ and grab the latest microcode or it could be a bumpy ride.