OK, I'm not an expert, but this is what I gleaned from other posts.
A perfectly balanced spring "barely" allows the slide to bottom out against the rear stop and then pushes the slide back into the battery without excess energy.
Too strong: the slide doesn't rack all the way and the pistol jams.
Too weak: the recoil forces the slide back too hard, placing unnecessary wear on the slide stop, and there may not be sufficient tension to force the slide back into battery.
Manufacturer's use an "average" slide to handle a wide variety of loads. If you're shooting lighter loads, then there might be value from a weaker spring.
For shooting hot loads you probably benefit from a heavier spring, which absorbs more of the recoil before the slide hits the stop.
Despite what I wrote earlier, my normal MOA is not to change things unless there is a problem or a well-defined benefit. My CZ 75B (standard 14 lb recoil spring) shoots great. Therefore, I probably will not consider any change until it's needed. It's just good to know the options.