The first time I saw it years back I was skeptical. As foremost a hardware guy I saw instructions in transistor count and gate delay, all that spaffed away on 16x16 multiply and you couldn't spare one flip flop for an overflow flag? Preposterous!
But the software already written was cool enough to convince me it was worth emulating, and once you've got an emulator you may as well write some software. A few short programs and I was in love. It's not about running code efficiently, it's about making it fun to write efficient code.
No sharp edges, no corner cases, generally minimal machine state. The cognitive load is so much smaller than any real world assembly I've used.
I didn't mean to write such a lot of meandering offtopic fluff, but damn, I just love that little guy ( ⊖-w-⊖)