For me its both.

A giant scale airplane for me is easier to assemble. The pieces are larger, typically less fragile and make more sense visually for me. Yeah the build table is a lot bigger and manuvering the plane around can be tricky... but hey...

As for flying, its been well said, bigger flies better. You would honestly be shocked at the difference flying a 70" WS Jug and then flying a 90" Jug... its almost miles different.