Of course, the answer to your question is position
dependant.
What position in the bank are you even looking for? Teller?
Financial planner?
There are few thousands of people who graduate with a bachelor in
business with a major in banking or even double major in banking
and econs.
How do you think a diploma fare in comparison with a degree?
Sad to say, the working society is very "paper" driven. Try to
think from an employer's perspective and you will realise the need
to constantly upgrade yourself.
Life is like swimming against a waterfal; you either give it your
best, get out of the water into a comfortable position or you let
yourself drown.
There is no remaining stagnant, when you find yourself not
progressing - you're already falling behind.
Good luck, TS.