When the suitcase is packed with over 18-20 kg of load and pulling on the handle, I can feel the handle ( on the longitudinal side) to the casing being stretched sufficiently. This gives me the uncomfortable feeling that if more weight is put into the suitcase, it may just break.  In addition, the roller wheels only allow single directional movement (i.e front and back movements, but not side to side movements), which may be inconvenient in certain situations.

Other than the above restrictions, it is still usable.