Well if you get that Vita you can always play Ys Seven and Oath on it. Just get them digitally.
But I have Seven and Oath. That's the reason why I want to get a PSP.
Well I'm not sure why you bought games for a system you don't own, but they're only $15 each on the PSN (and I'm pretty sure they've been on sale before for less than that before...), so it's probably cheaper to rebuy them than to buy a PSP just for those two games...
They aren't the only PSP games I own though. I also have TitS, TO, R-Type Command, Gungnir, Persona 1, Persona 2 IS, and a few others.
And to head the next question off at the pass, I was borrowing a PSP to play these games on for quite a while with the intent of picking one up around this point in the console's life cycle. Unfortunately, some random asshole decided to try to corner the market in used PSPs and hunted down/bought up every single used PSP in town to flip on Ebay for a profit (well that, and the fact that the FE 3DS actually made it out of Japan after all so the money that was set aside for the PSP went into that instead).