missing documentation

[Thomas Bushnell BSG]

I understand what happens if I import a QIF to start a new set of
accounts: the wizard works with me to figure out what the file says, and
then sets up accounts.

But I haven't got a clue what happens if I import a file from my bank.
Why would I want to?  What would happen?  The documentation assumes that
everyone knows why.  I don't...

What happens if you connect directly to your bank using aqbanking?  Who
would want to to? Why?

Thomas