I also like having expanded storage. But if you actually care about privacy?

You want the minimum amount of data on your phone at any given time. Your recent camera roll, any cached music and apps, and that is really it. Everything should be offloaded to your private storage ASAP

Because for as shit as google and apple are? You can also remote wipe those devices. less effective if it is a government agent that has it, but it is a thing. And, depending on the storage setup, that sd card might be raw dogging it to begin with.