For some of us, the information feels 25 years too late. So why bother?
Järvensivu explained:
The tutorial is demonstrated by using FS-UAE Amiga Emulator to allow for the widest possible market - not everyone interested in the topic will have functional classic hardware. And they set the emulator to it's widest possible market: Amiga 500 with kickstart 1.3 ROM image and Workbench 1.3.[L]earning how to write programs for [Amiga computers] can be very educational. Amiga as an environment is much simpler than (for instance) modern PCs. This makes learning low-level programming on it faster than on more complex environments. Although the hardware architecture is quite simple, it has some computer system design features that are still in use in modern environments as well such as DMA and interrupts. On top of being plain fun, writing assembly on Amiga teaches programming concepts that are usually hidden by higher-level languages and modern operating systems.
They walk through an example of putting graphics on-screen, explain how and why to talk to the various chips and debugging the code. Pretty cool stuff.
If you decide to take the plunge, and get stuck, it's worth noting that there is a StackOverflow for retrocomputing.