Right. That was sort of my point, I understand it is useful to consistently lift and move heavy stiff without fatiguing oneself. I think if you were to improve it to say, 250kg it would fit a lot more usecases. Overengineering, in my opinion, would be asking for an iron man suit.
I suspect that when you get up to 250kg you run into stability issues as much as strength issues. Even if you could lift it easily, it would be really tricky to hold it in a way that you won't tip over and drop it.
