I have upgraded the trigger on 10 pistols and 3 of my rifles. The biggest difference on most pistols is a more accurate and faster 2nd shot due to reduced travel and a more positive reset. I have had a few that the pull required so much effort that I couldn’t even keep it on target with one hand.
For a long distance rifle shot, a smooth and reduced trigger pull can be the difference between keeping the target in view for a follow up shot or needing to re-acquire.
That said, most of my guns don’t have these upgrades. They could probably be made better but if it’s not a noticeable deficit then the improvement would likely be minor as well.
Lastly I should mention that three of my Sigs got triggers because I wanted them to feel the same when switching back and forth. Other wise someone might think I regularly bought guns with a substandard action. Ha ha.