The download is "exclusive" to registered users through official channels:

Kickstart ROMs are copyrighted material. To obtain version 3.2.2 legally, you typically have two main routes:

This architecture made the Amiga highly modular: the ROM supplied a consistent runtime environment while the disk-based Workbench and additional libraries could be upgraded independently. Embedded routines in Kickstart also enabled rapid cold boot times and robust support for preemptive multitasking—advanced features for home computers of its era.