Virtually every bank now has a banking app. They all take security very seriously and have different approaches. It is up to you to consider if you feel that you can manage your banking on a tablet. If you do use a banking app, it is advisable also to have a password to unlock your phone/tablet, don’t put the app on the front page, never keep your passwords on your device and turn on the “find my phone/tablet” feature (and enable location services). This way if anything did happen you can manage the situation effectively.