Over time you'll save thousands on ammunition. Moreover, you'll learn how to control the quality of your loads and optimize each firearm's accuracy.
I have a colt H-Bar that shot about 3 MOA with most factory loads. It also had trouble cycling certain brands of ammunition. It's a super picky rifle, and I was about to unload it, but, I stumbled across a load that it absolutely loves (it really likes hotter loads). That thing now shoots about 1 MOA without any reliability issues whatsoever. It's a tack driver.
I don't shoot factory loads in any of my guns (with the exception of .22 lr, 7.62x39 and 5.54x39) anymore.