> Does anyone actually do this?

Yep. I've been using an iPhone since 2012, so about 14 years. I do a local backup to my Macbook and then perform upgrades via USB, I don't do over the air upgrades. I also don't sync my photo albums into iCloud. I do have iCloud backups enabled also. It's not even a concern about privacy, per se, it's a question of whether or not I actually control my data if its not in my possession. More copies is good for resiliency.