Anything you interact with on a daily basis. Keyboard, mouse, desk, monitor... If you're going to be spending a couple hours a day at it why not treat yourself?
I would login to my phone to do something and it would dismiss my unread notifications from the lock screen. Never got into the habit of swiping down to check notifications as there isn't any indicator like on Android. On Android I'll keep a notification up until I get to it, so it's always a reminder on my lock screen.
Ideally. Depends on the update time too. I know flashing ECU tunes requires a battery topper. I've also killed a car battery modding my infotainments firmware so it's totally possible. But most likely Subaru is doing it out of an abundance of caution... Don't want an angry customer coming saying the update killed their battery
On my phone I double tap the power button to launch the camera, then use the volume buttons to snap a pic. Doesn't require me to look away from the road. Framing isn't always right, but it's 100% doable without taking your eyes off the road
That's my strategy. Leave the notification there until I have to get to it