It just makes sense that a liquid paint-on system offers more protection for the protrusions coming out of the roof and at join areas. No more hit & miss and hope that the waterproof system adheres to the surface. If the surface has been prepared properly, the adhesion of polyurethane will complete its task of waterproofing.
No more delamination (peeling off the surface) of the product over time, just pure adhesion.
Try take an apple peel off an apple vs taking the peel off a naartjie. Which is easier?
With time, the naartjie fruit will delaminate from the peel.
Ever seen an apple peel come adrift from the apple?
Polyurethane is like the peel of an apple.