I've bought an Alfa adapter 10+ years ago because you can use them in promiscuous mode. So you can snoop wifi traffic, listen for handshakes and doing so crack WEP/WPA (wifi) encryption.
They have a little. 5ghz is more common, so you won't get any thing there. WPA2 is significantly harder to crack, and I usually do it on GPU with pyrit or hashcat-ocl and a wordlist. WPA3 is out now, too, and I'm there aren't really any well-established procedures for it yet.
Just FYI WPA2 is pretty solidly and quickly broken (lookup KRACK attacks). WPA3 is unfortunately already partially broken (though currently joining the network / password breaking aren't fully broken, see Dragonblood attacks).
KRACK was a nonce re-use, not a core protocol flaw. WPA2's flaws are more around un-encrypted control packets; i.e. I can de-auth you without having to get session keys.