Every factory firearm that is made for police or military use has a built in reliability factor so it will function under adverse conditions, like cold, dirt, dust, rust, etc.
When you reduce spring power, you reduce that margin to some extent. Whether that matters depends on how and how much you alter the gun and under what conditions you might use it.
But if the gun is for defense, it might not always be used on a nice clean, warm, clear pistol range. It might have to be used in rain or snow, in freezing weather, or after it has been dropped in sand, dirt, a puddle of muddy water or a pile of doggy doo.
Of course, the "carry for fun" crew cannot imagine that they might actually have to use their guns, or that a gun might be scraped or scratched or dirtied (oh, the horror!). (Of course YOU would never drop a gun! Not even after taking a 9mm through the arm?) But if you might really need a gun, you should consider those things and make sure you don't do anything that would turn a bang into a click. Your great trigger job could cost a life - yours.
Jim