It serves as your master archive format . You store your games as Nkit.ISOs on your PC. From there, you can convert them to RVZ for Dolphin or WBFS for a USB drive in seconds.
NKit v1.4 is powerful for collectors who maintain their own legal backups, but it's less useful for everyday emulation. The space savings are impressive, and the data integrity features are excellent. However, the complexity and need to reconvert before playing make it niche. If you want simple compression for Dolphin, use GCZ or RVZ instead. For pure archival of untouched ISOs, NKit is solid — but only if you understand its limitations.
You may legally use Nkit :