“But this functionality is mostly not needed in an embedded application, so the additional complexity of systemd is a cost without a benefit.”
On a Raspberry Pi 3B, the systemd init binary is about 200kB and dynamically links 26 libraries. SystemV init is 40kB and links only the C library. systemd adds about half a second to boot on that board, the opposite of its pitch. The people who like it most are distribution managers, and they are not the ones shipping devices.