Hehe, good point - it was an available choice though so I picked it dag nam it!
Hehe, nice explanation
Of course you are right about the expansion bus, but that is not the only one - when (as you say) you have CPU, sound, blitter i/o or whatever all fighting over say - chip RAM accesses.
This is why you normally get a speed up (especially in the A1200) just by adding some "fast" memory. Because then the CPU is free to do what it likes with it's own memory (hence "fast") without having to wait for another component to finish using the bus.
Bus Arbitration -> Bus Arguments & Bickering
When an emulator gets this level of accuracy - then we hit the golden time of emulation IMO.