In the case of your .380 the benefit is that it gives you the bearing surface and contour of a heavier bullet with less recoil than the heavier bullet.
Life Member NRA, TSRA
Smokeless powder is a passing fad! -Steve Garbe
I hate rude behavior in a man. I won't tolerate it. -Woodrow F. Call Lonesome Dove
My favorite recipes start out with a handful of used wheelweights.