When I first picked up the Mecha Knight Kit I found myself using it sparingly; at first as an extra knight, eventually as a decoy to borrow time. Their Malfunction ability can be a burden on any travel, especially if unwitting allies are too close to the mechanical soldier. Fortunately, between that passive impediment and its basic ability for combat, it can become useful if applied in the best of situations. I found this to be most evident in a particular situation.
For those of you who are able to play the Operation Crimson Hammer expansion pack, you may know of a swift little gremlin that slips in and out of cloak to do all but help you cross busy highway traffic. These Ghostmane Stalkers normally roam the site of Seerus' compound between the second and fourth floor. When I first attempted the campaign on T1 and encountered these buggers, all I could think in mind "NOTHING PREPARED ME FOR THIS!" in an exaggerated manner. With my first push through it, I survived with no deaths, somehow (I used my maxed 2 star gear).
Upon my second or third go (I forget which), I happened to come upon a Mecha Knight Kit as a dropped item, I picked it up without the intent to use it. And then I arrived at the area where the Stalkers first show. To ensure that I would have a better chance to survive with half health of my maximum health, I deployed another agent in my solo campaign to take some of the damage.
Lo and behold, that Mecha Knight was more useful than I gave it credit for. Unlike myself who could barely detect which way those stalkers were to close in from, I noticed that the Knight itself attacked as if it knew (of course). However it was having trouble hitting targets that would neither stay still nor stay visible. So for once I thought that I should assist it instead of it always coming to my aid. From across the screen to its right side, I fired one to two shots in its general direction to avoid the stall from reloading weapon.
Each shot that successfully hit a cloaked enemy knocked them out of their invisibility and knocked them back. Afterward the automaton would take advantage of any lone enemy's stall and deliver a combo. Eventually this became the plan for dealing with them on this floor as my shots fired were less frequent. For as long as it was working and I remained on that floor, it followed and I assisted it.
Among other occurrences, that was one of the single, coolest thing that I have witnessed.
I know that Non Playable Character's (NPC), once rescued, are quite a help as well. However the facts remained: there was no NPC for the assist; there was no partner for the assist; as with solo campaigns it was me versus enemy forces; with the deployment of the Mecha Knight, I merely took a back seat to the show that ensued.
And it turned into the Mecha Knight vs the Ghostmane Stalkers.
That's what I do! Those little Knights could snuff out any stalkers. They would take care of one or two enemies while I took on the horde, otherwise. Pretty useless except for that and finding hidden enemies. Pretty sweet for leaving them out, like that, Gremmies.