The original Ultimate Ninja Storm 3 disc version requires the disc to be in the drive. A PKG installer allows users to write the game directly to the console’s internal hard drive (HDD), leading to faster load times, reduced optical drive wear, and the convenience of launching the game directly from the XMB (XrossMediaBar).
Unless you are a completionist hunting for a specific glitch in the vanilla version, you should prioritize the "Full Burst" PKG. It is the definitive edition of the game. naruto shippuden ultimate ninja storm 3 pkg
You don't actually need a PlayStation 3 to use a PKG file. The emulator for PC can install PS3 PKG files natively. The original Ultimate Ninja Storm 3 disc version