I see there’s been a change in the most recent firmware: if the display is off and a checkout is created, the display wakes up and the checkout proceeds immediately. This is very welcome!
I’m reasonably sure the display now goes to sleep on its own while in terminal mode, because I came in after leaving it for the firmware upgrade and found it blank, but I can’t work out how long it takes. I have my terminal set to “Turn Off Display After 1 Minute” in the Display settings, but it’s definitely taking longer than that.