The entire operating cycle of an auto pistol depends on those springs.
They control how the slide decelerates allowing the fired case to eject, and then how quickly the slide closes with a new cartridge.
A weakened spring can allow the slide to travel to quickly rearward resulting in the front edge of the ejection port striking the case as it tries to exit. This can result in all sorts of funny things, including the case being thrown back into the breech area.
The next round will move into the top position under the magazine lips to early since the slide cleared.
Now both are trying to occupy the same space.
As the slide starts back forward it will move slower than desired.
Since it has less momentum, when it encounters the rear edge of the cartridge in the magazine it may loose enough energy it cannot return to full battery.