That mechanical tail was made to help labourers with balance while lifting.

And frankly, what do you need a tail for to balance for when you're on all fours? It's harder to balance on two feet, I should think. (Cats use their tail as a rudder, perhaps, but that's not balance per se - agility more like). And I've seen raccoons run away with armfuls of food while on two legs (like human ancestors running to the nearest trees across parkland, with handfuls of carrion or whatnot). I don't think lack of a tail has anything to do with being a Master Species, or even walking on two legs (and theropods say hi, too. Human bipedalism isn't the only way to be bipedal, and when it comes to technology? Well, the whole point of it is to overcome physical shortcomings, so how it would manifest would depend on what the species needed it for. Man is just generally pathetic and found himself in an ever-tightening spiral of technological dependency ...)

Did you check out the video? Looks like a helpful product to me.