The 2x1 wifi card are intel specific while the 2x0 cards are CPU agnostic. As long as you have a card model ending in 0 you're fine to use any CPU.
As for why they did it I'd assume its slightly cheaper to build a 2x1 chip than a 2x0 as offloading the functions to the CPU would mean less components on the card itself. When you're selling 100s of millions of them every little bit counts.
As for why they did it I'd assume its slightly cheaper to build a 2x1 chip than a 2x0 as offloading the functions to the CPU would mean less components on the card itself. When you're selling 100s of millions of them every little bit counts.