Many accelerators add faster CPU, Extra memory and IDE using original Motorola cpus and FPGA/CPLDs - what's cool about this is that it does all of that mostly in software (there's a CPLD to get the 68000 bus timing perfect) in real time without missing a beat.
System emulators like WinUAE don't have to be perfectly accurate with their timing, you can frame skip and do other tricks to catch up lost time but you can't do that when interfacing with real hardware like this. If you don't get the timing right it will crash
