I never used a banking app nor Android Auto. For me, these are not reasons to go with a less secure/private OS.
Most of my purchases are with cash, once in a while I'll use my credit card so I have no need for a banking app. Usually, I do my banking at an ATM.
As for Android Auto, my phone stays in airplane mode most of the time. In order to use AA, I would have to allow constant cell-tower tracking by turning off airplane mode.