I use the Perth HSBC and it is a strange place, everything that you might normally do is done by machine - there is possibly no requirement for staff at all. There are staff, I have seen them arrive and walk through to the back. Withdrawing money is automated, paying in is done into machines that count your notes and reject any for having the tiniest fold in one corner. Even if it was a bank you just got them from.
But in the middle of all this space age scene, a human stands. They are employed to say "Hello", "Thanks" and "Would you like me to swap that for a different twenty".