It won't completely replace epoxy...

I mix polyurethane glue 50-50 with yellow glue for joining/repairing foam wing core panels, and for filling where chunks were ripped out of a foam wing. Tape the joint or patched area and the foaming action won't rise as much beyond the airfoil shape. (less sanding and shaping) Occasionally there's a huge air bubble that has to be filled again when filling a large void.
The 50-50 mix is also good for some installatins of bylkheads in fiberglass fuselages. Sand the fibreglass a little to ensure the mold release wax orsurfacing wax is gone. (epoxy or poly resin will have a waxy surface, bad for bonding ANY glue.) And... its virtually fuel proof.

Its good stuff... but It shouldn't be used for dihedral braces in built-up wings. The air bubbles mean less bonded area.