A heavier spring makes some parts rub against each other harder, causing it to wear faster. The parts would wear anyway, it's just a little faster.
Personally, I like the standard springs for the comp and super on my normal stand alone CPs. However, when I hacked taller and heavier trigger&thumb handles onto my comps, I had to switch to the heavier springs to compensate for the heavier sticks. I can image the the steal replacement sticks, and the extra long sticks replacement sticks, also needing the heavy spring.
(I also like the point armad brought up.)
Mostly though, it's how you want it to feel.