A couple of Qs about PMK

[Pilsener]

I have been reading about PMKs, and how to capture, extract...etc....
That part is no problem.

But then the guide listed this:
We can now proceed cracking the bettercap-wifi.handshake.pmkid  file so generated by using algorithm number 16800:
/path/to/hashcat -m16800 -a3 -w3 bettercap-wifi-handshakes.pmkid '?d?d?d?d?d?d?d?d'

Now I started to wonder:
1. How do we know (in this example) that the passkey consists of 8 digits?
2. Is there any way to obtain (from the PMKID) any clue about what mask to set?

[undeath]

Now I started to wonder:
1. How do we know (in this example) that the passkey consists of 8 digits?

external intelligence

2. Is there any way to obtain (from the PMKID) any clue about what mask to set?

no

[Pilsener]

So what's the advantage of using PMK instead of .cap?

[slyexe]

So what's the advantage of using PMK instead of .cap?

PMK can capture the appropriate data without clients.

[atom]

Most important: no defective handshakes