When I see the term "bulged" reeds mentioned here all I can think of is "bombate" reeds (in some form of translation).
Bombate reeds have indeed a bit of a bulged surface, and this supposedly makes them stronger and better sounding.
But I'm not a great reed expert: I have not yet encountered an accordion with "bombate" reeds in the limited amount of repairwork I have done.
"...holding one to the light, you CAN see the curvature"
Does it curve along the long axis or across it?
If at right angles to the long axis, it would seem to conflict with the direction of vibration and exacerbate metal fatigue ?
But, obviously, it must work, or they wouldn't be doing it!!