What's the point to them? Why does it cost so much? Why is it only sold by the Outcasts, Gallia and that Freelancer base? Why is it Outcast manufactured, when they already have the Inferno? Is that 110 power usage that great? Is it the Thrusters' equivalent of a Codename, but cheaper?
It's Disco's trend. You can use Enhanced one but for a very little tiny advantage you must pay alot. Same goes for CAU8, you can use CAU7 but if you want a little difference then pay double price. Same works for everything.
Also for OC, well they are developed by OCs by infocard, but who cares, it's open tech so no one had any concerns about it.
repair costs are based on purchase price. that is why it costs much to repair.
about the outcast origin - it is just the inRP origin. it is free tech. much like cau8 is meant to be order (back then to make their light BB more durable compared to the various pirate behemoths that had cau4 or so), the ripper mine is hessian (less damage but higher tracking speed to catch their slow titan enemies), the minirazor - i don t know but back then it was manufactured by a faction, too - or even the Nova tech, when it was still a cannon doing 48k damage from a VHF. it was mostly associated with the GMG to display how they defeated the capital ship wielding rheinlanders.
it is mostly a status symbol rather than a change to be very efficient.
it is like a battleship scanner, a spyglass scanner or flying around in a freighter with a cau8. vanity, RP, self satisfaction, bragging "because you can" - pick one.
Diminishing returns doesn't really mean much when there's a massive surplus of funds and very few avenues to spend - that's why you see ships with equipment that are the "best" in their categories that offer a negligible but appreciable increase in performance above the normal high end class, but with a massive and disproportionate increase in cost.
TLDNR: Cheetah thruster'd BS scanner'd CAP8 cruiser makes my shortcomings feel bigger.