Commando is one of the most fun units in the game. It is the only bot that can survive falling from a shot-down air transporter. Also it has a personal radar and radar-jamming device.
Use this fact to drop it straight into an unprotected enemy base and tear it down with mines » The Commando can build medium mines.
Pro players use it to “steal” resources. To do that, damage a structure until it has few % of HP and then reclaim it gaining all the tasty metal. Falls short in comparison with regular combat units. Try to avoid engaging with them.