You can totally use emojis as passwords. You can probably even make this a policy at your company.
Edit: I thought this was an obvious enough joke, but just to clear things up: Only do this if you hate your company and everyone working there.
It is very useful for your printer to have LAN access so you can print jobs wirelessly from your laptop.
But printer was just an example of a low-tech device. It could have easily been your Nintendo 3DS that might implode if your SSID had an emoji in it.