Fight command is great, huh? :3c You move to max range and then you start shooting. But some things don't want to stay at max range. Sometimes you just want them to get close and keep chasing as the enemy runs away, and for that, you need a command that doesn't stop your units from moving once they get in range.
So that's the Melee command. :3c It does what Fight does, but then once those units are in range, it acts like a Guard command but for enemies, following that unit around until it gets right up in its face, doing its best to never let it get away, keeping that unit inside its attack range at all times and allowing laser damage to ramp up to maximum.
The Attack circle is fine for gunships and scouts vs early game scout harass, but what the attack circle sucks at is following units that are being microed away from you, because Attack commands cause units to close to its max range and then stop moving and attack. Melee would make units keep going until they get right up in its face.
It would be no substitute for proper surround micro or runby micro, but it would certainly free your apm up for other things if what you need to do is have one set of units chase after something that wants to kite you while you also micro a different set of units that needs to be babysat. It could help reduce the number of things that need to be babysat at any given moment.


