Now go out and lift it once per minute for 3 hours and see how you feel.
True however family business is construction a little experience here
aside from OHS concerns where everything comes in maximum 20Kg packages (Australian OHS rules noticed some stuff from the US is 25Kg) 25 years ago most of these packages came in 40Kg particularly cement
moving 20-40Kg at a time with a little practice and the right food you can do this all day and you won't like like a steroid taking gym junkie which BTW are useless at this kind of work
What I can see this helping with if they do get it to lift 100Kg or this awkward/hazardous items where 20Kg even unbalanced can be very difficult to manage