i see no reason to go down in bow holding weight unless prescribed by physical ailment, as long as that holding weight is in compliance with the hunting venue legal regulations, and is commensurate with the type of game hunted.
a 40# holding weight may be legal and fine for small game such as rabbits, or thin skinned game such as deer, but at the least will be questionable for other types of larger, thicker skinned and boned game.
add into the equation the most important part, the arrow - it must fly well, have a sharp coc broadhead, be of reasonable mass weight, and the operator (bowhunter) need to be able to consistently hit the mark under hunting conditions and at reasonable shooting distances. better to have superior accuracy with a 45# stickbow than a 55# stickbow with limited accuracy. all predicated by the game to be hunted, too.
if yer not physically challenged, it will pay to pack a bigger stickbow hunting punch. won't take long to increase holding weight by 5 to 10 pounds, and if that deer 'jumps the string' and the broadhead hits in a less than desirable spot, yer chances of a good kill are increased.
jmho and ymmv.