Lies!!! to exploit a PSP you have to be able to run unsigned code, such as a downgrader on it, this isnt the easyest of things to do, for a start you need the correct type of firmware, some times even GTA:LCS is required, secondly you have to flash the hardware, which leaves you wide open to the possibilty of bricking.
You don't have to buy a bunch of stuff to get the DS to run games it shouldn't, just one product will allow you all the freedom you want (I wont post name's here as DC emu do not condone piracy!)
The PSP can play gammes from memory stick once running custom firmware or by using loaders, but Sony Memory Stick Duo is expensive, compare this to the DS method of using SD cards and it works out a lot cheaper and easier.Piracy on Nintendo DS is rife, just as much so as PSP, the fact that DS games are so much smaller than their PSP counterparts contributes to this.
The console has nothing to do with the games in that respect, I dont see Loco Roco "looking" any different to your so called "Kiddy games", I have seen "over the hedge", "cars", "daxter", "Ratchet and Clank" on PSP, all can be classed as kiddy games if you want, but there are many different types of games to play on both systems, I dont believe that just because they look cartoonish they have to be, as you put it "kiddy", I dare you to get aquainted with MArio Kart DS for a few hours and tell me it isn't a master piece, or that Mario 64 DS isn't one of the most enjoyable games you have ever played.
the PSP has some fantastic hardware, and I am vbery fond of mine, the problem I see is that Sony do not know what their poor little console is! is it a games console, an MP3 player, movie player, internet browser? it is a jack of all trades, and unfortunately a master of none.
I own both a DS and a PSP, my DS is gathering dust since I gained my PSP, but this is purely because of the homebrew scene and the many glorious games and applications that have been released for it, the comercial software and games fopr PSP have very little appeal to me, and I rarely buy a game for it, mainly playing on old SNES and Megadrive games.