• When you’re trying to make it level and hit the studs with your fasteners, it’s much easier with a stick than a whole cabinet carcass.
• Cleats make the cabinet easy to install and remove.
• French cleats have a substantial amount of bearing surface and are extremely stable as a result, even without additional fasteners.
  • That said, for a cabinet I would probably still drive a screw from the inside through the back panel into the cleat to eliminate any chance of a strong bump from underneath knocking the cabinet off the cleat. You know, like when you drop that last m4 nut on the desk and it bounces into the corner and you have to reach over your project and soldering iron and cup of coffee to retrieve it and then stand up too quickly in triumph and bang your head off the underside of the cabinet…