That would be very Important, since there were a spreading news about some of the people recieves a log in attempts with their account in several exchanges but only fail during 2FA.
Its a very Important precautions, what if you get hacked while your away with the same password in several exchanges? That would be a very devastating huge loss.
One can still get hacked even with Two-factor authentication and different password, it's most times inevitable. I usually use different passwords and the 2FA thing, but the best protection one can give to their exchange is to never leave a huge amount of coins in any exchange. An account can be extremely secured but still get hacked. Hackers can do anything just to get what they never laboured for.