The phase transport stays cloaked while moving. It is the only cloaked transportation unit in the game. It is also the only cloaked unit which can crush infantry. It remains cloaked crushing.
The phase transport can also detect other cloaked units.
Armed with rockets, the phase transport can be effective against light armored units or even against ore trucks when in large numbers.
The phase transport is not to be confused with the transport naval unit.
A swarm of phase transports can crush large infantry blobs in seconds. It is similar to the APC in that regard, but since it's cloaked, the enemy cannot counter-attack, unless they have cloak-detecting units among the blob.
A phase transport can be parked in front of the enemies ore refinery, making the enemies ore trucks unable to unload the minerals. The enemy won't notice it and has to invest in cloaking detection to be able to destroy the phase transport.