The only benefit to a conventional edger is if you are constantly having to clean up edges that have not been maintained. Even then, I would have a tough time not picking one of the heavier stick edgers instead.
I just couldn't see why to use a conventional edger when I have the biggest Stihl edger (FC110 engine) mated to a curved shaft instead of the straight shaft that was on it originally. (Stihl did not offer the FC100 in my region at the time).
Overgrown grass growing a foot or more over the sidewalk? No longer a problem with this badboy. Preferred the curved shaft since the straight shaft had me walking up on the grass till I learned to hold off to the side. Still then it didn't feel natural.