Shock value against the human troops? Superior infiltration capability?
For morale, we can do much more shocking things for less impact. Besides, we don't want the humans to panick so much that they switch to region destroying weaponry, or ask for help from another race. We have shown that we can hack their networks; Just sending a mondial message for surrender will be more persuading than fielding a small army of cyborgs against them. In the first case they might be willing to surrendeerr, in the last one they will most likely fight to the death.
As for superior infiltration capability. I doubt it. The amount of knowledge we would need to succesfully connect the humans brains to artificial system is tremendous. After all, we would need to have a perfect connection, or they will just look odd. That technology we could use to make a android, which can infiltrate just as well, and is more reliable. The best would be to send a normal human, but that might cause problems of loyality and such.
Besides, sending humans gives other problems, because they will either be criminals or kidnapped. So that will certainly get the attention of security systems. Now, adding an android is not that hard. After all, there are many more people registered then there are criminals or missing people, so those databases will be less secured and less often checked. Sure androids might get problems with security scans, but the same counts for cyborgs. Except,when these modifications are mundane, but then that means that they wouldn't have any advantage, making it pointless.
Cyborgs
-Mechanical limbs and organs
-Brain machine interface (Harder to do, and useless. Our brains don't work like theirs, so the technology would only work for them)
-Human psychological studies (You do want to do some studies first, ratehr than sending a random person in.)
Androids (We can also go for a simple robot, which would just need the AI and would be less suspsicous)
-Mechanical limbs
-Working AI systems (Might be usefull for lots of stuff)
-Human psychological studies
The humans posses both robots and implants. Sadly, when going with heavy modifications both will arouse suspicion, and trigger alarms.
Last, why would we even want to send troops to infiltrate. We can control their networks, have spy drones(both mechanical and organical) and automated microcams are well within our reach.