Because it has a memory card doesn't mean just any old code will run through it. If it weren't for the freelauncher and the fact that GP opened up the system(included the freelauncher in the BLU) , you wouldn't have it on the GP32 either. All code MUST BE DRM SIGNED in order to run. un-signed code will *not* run. There are chips in the PSP that only allow encrypted code to run. Could someone crack it? maybe. It would have to be a hardware mod probably just like the PS2. If you are ok with cracking open your PSP and soldering in mod chips then you are ok, maybe. It might just be too much of a pain to do it in that small space.
Think about it. If it was that easy all it would take is an easily obtained blank memory stick and an internet connection for the public at large to gain access to thousands of free games that would kill or severely hurt software sales. Do you really think Sony wants that? No way.
Third party developers also don't develop for systems that are un-secure as they want you buying their game and not getting them for free.
Emulators on PSP are not a sure thing, at least not for a long time, if ever.