I use Mint just to view my bank account, if i ever lose my device, they still need my pin number to get into the app(not your bank pin, any pin you set) and i can always change the password of the account online.
Over a cell network is probably THE safest way to bank. I trust that Cyanogen hasnt done anything that will steal my bank info.
Sprint HTC Evo 4G - Rooted Stock ROM
Pre-Ordered HTC Dream (G1) - Rooted Cyanogen Mod 6