Micromanaged, they’re great for controlling space, killing any Engineers that venture outside the enemy base, and generally getting the upper hand.
You can also put them inside a T1 gunship and they’ll fire, creating a Chariot Gunship. Of course, remember not to rely on them for actually defeating the enemy base; if you have air superiority, go straight for their Commander.
(can fire from transport)
Sonic Pulsar (Direct Fire)