Practical use - dragoons & zealots in formation that they aren't too close together - useful versus Siege tanks. Line formations in PvZ - zealots moving in a line. Mutalisks air formation with separate spaces vs archons/corsairs. Circular formations for M&M that would keep them in one moving group...
2. Unit Kill Order - this means u could set marine to preferably attack scrouges before other units, setting zegling to be prior to attack before ultras for zealots/archons, tanks prefering dragoons before zealots when using attack move command.
I think both of these have a logical base in the real world when commanding an army.


it's like adding mass spellcasting, like haveing 12 templars storm with everyone but just one templar fire of the storm like in war3. ^^ would be sooo much better for pvz and tvz (irridiate)