I guess this is a space-saving measure? A now-defunct company called Modern Maid once produced the KBT-100, a hideaway toaster meant to be mounted and hardwired inside a wall:
Listen beautiful relax classics on our Youtube channel.
I did find a video of it…
…but the guy giving the demo doesn’t tell us the one thing I want to know: If you push it back into the wall when it’s toasting, does it automatically turn off? (If it doesn’t, I can see why these aren’t on the market anymore.)
Source: core77