I can see your point but if you put the hand brake on the a frame it locks the wheels a trailer would be better but its more to tow and more to store
my motorhome is 5 1/4 ton 6 wheeler so will stop a 1300kg qubo
I don't make the system but it works
they are fitted by car a tow / tow tal & others
I have towed an alto and a Suzuki jimny on a aframe and they all tow fine
I have also towed on an inter trade unbraked a frame if you have some thing big to tow it with its fine . I have also towed boats all around the uk on unbraked trailers + the brakes don't work on most boat trailers after you have dipped them in the sea a time or 2