Oh, where to begin...This unit is by far my favorite because it opens so many doors
1. Assuming you clear out tach guardians ahead of time. and the AI has no fleet units that decloack, you can use these to transport any fragile unit in AI territory, including for deepstrikes. Engineers, research labs, transports...
2. Have a near melee unit(s) that always dies by enemy fleets before getting in range? Group move em with a starship, and they'll get in range. Lightning warheads are worth the micro.
3. They can be used on defense to prevent the AI from shooting fragile / expensive unit. Research labs, civilian spire posts (just thought of this, I'll check if I can do this later), the occasional nuke just laying around...
4. After you finish building it, you can cloak MK III stations so they can research in peace.
5. Cloak shards.
6. These things should just marry your warheads. From the moment they are built, till the moment they are detonated, they should be buddied up with cloaking.
This is such a fun unit because there always are new uses I put it toward.
EDIT: Also, you can't beat the price.