I have done some math on the usefullness of cargo disk.
the time it takes with out a cargo disk is just walking to the point of pickup and then recalll back lets say t
the time it takes to get a to and back with a cargo disk takes compaired to the privious time this is t+t/(1-speed recuduction)
so I can take t+t/(1-speedreduction) load home for every time I get a load from a cargo disk home
if formula were Cc is carying capisity od the cargo disk and Cn is the carying capisity with out cargo disk and sr stand for speed reduction
(Cc+Cn) *t = Cn*( t + t/(1-sr) or simplyfied. Cc = Cn /(1-sr)
As effect I don't see me using cargo disk for the time being.