[socks]

not really. banking systems have firewalls and access controls. quantum computations would be useless.

[webXL]

Those don't really mean anything when an attacker can eavesdrop on customer and employee comms and possibly redirect transactions (MITM).

[kelnos]

Banking communications and transactions will all be protected by quantum-resistant protocols and ciphers well before that will become a problem. Most of these already exist, and some of them can even be deployed.