Yes, that's true; my point is that the pi will happily boot whatever, unlike the Pinebook Pro which has a default bootloader on internal storage that ignores the SD card. So a distro/OS has to add the pi-specific bootloader to their SD image, and that's a pain, but they
can't do anything to make the PBP work, because the machine won't even pay attention to their SD image.
EDIT: Actually I guess the Pi 4 added an onboard flash chip with an early bootloader, but I can't figure out if it impacts the boot order or changes how hard SD boot is: https://www.raspberrypi.com/documentation/computers/raspberr...