That the "Done" buttons in an upper toolbar have persisted for so long after they were reachable is a bit embarrassing. It was a great design for the original 3.5" iPhone screen, started to get iffy on the 4" iPhone 5 depending on how big your hands are, and has been stupid since the iPhone 6 in 2014.
There's still other buttons up there, but you can get away without them more often than before. I guess the concession is that phones are assumed to be two handed devices now, which I think is unfortunate. If I want to two-hand something I have an iPad for that. Give me a one-handed phone with the same camera as the flagship. RIP iPhone SE.
More on the popover cards here (EDIT better link): https://medium.com/@hacknicity/view-controller-presentation-...
[EDIT] I think part of why I haven't made it part of my normal use of the phone is that the shift-from-normal-one-handed-grip-to-double-press-home-then-back-again maneuver is risky (of dropping it) enough I'd shy away from it and just use two hands.