There are several advantages for this placement. The Ethernet port was relegated to the power supply.
The power adapter itself has a new magnetic connector and doesn’t use one of the computer’s USB-C ports. The only I/O ports appear to be a 3.5mm jack and several USB-C ports. The M1 iMac sports a new design that’s much thinner than the last generation and Apple likely didn’t want to make room for the Ethernet port. On the surface, this seems like a silly placement of a critical I/O port, but there’s a good chance this feature could hit future Apple laptops where it makes much more sense. Among the numerous updates and upgrades is a new power brick that sports something special to Apple’s lineup: an Ethernet port. Apple just announced the new iMac powered by Apple’s own M1 silicon.
