Wrong. The psp gpu is very similar to the ps2 gs. All it can do is to display polys and point sprites. The rest is up to the sw.
Besides an emulator can't benefit from any kind of acceleration apart from filters and high bandwidth. You must render the picture point by point as it happens on the screen. If you can render that in the videomemory fine, you might as well switch to display it, if you can't, you need high bandwidth to transfer into video memory.
Being emulated does not mean being playable, good or acceptable. You can emulate it one frame a second etc. It will be emulated but it will be unusable.
Amiga is one of the most complex systems ever made to emulate, and it requires considerable raw cpu power to make it happen.
The psp has as much cpu power as advanced cell phones, and mid-range pdas have. There was no need for more as power consumption was a big problem, besides all the graphics work is done in hardware. However this is the thing from what an amiga emulator can't benefit from.
Don't expect anything more than 20 frames max and only in games where the coprocessor utilization is very low, ie think in Bard's Tale being playable, not Turrican 2.
The point is: buy it for what it is, not something you hope it does well, since it can't. You will be very disappointed.
If you want portable amiga emulation get a high-end pda.