Well, I don't have a Vita myself, but I don't see why you'd even have one if you don't have multiple reasons to keep it.

I bought my Vita relatively recently (end of May last year), so i still have a large backlog of games to work through. I'd keep it regardless though. I'm not a particularly sentimental person, but I've always struggled to get rid of my consoles :p

Ok. Because i still got Tales of hearts R, Sword art online hollow fragment, Ys celceta, Freedom wars and Shinobido 2 to finish. Ninja gaiden 2 to finish replaying.
Also because i want to keep persona 4 golden, mortal kombat 9 and wipeout 2048 on my collection and also because theres upcoming games like Liege, maybe digimon story, maybe tales of innocence R, new Ys, new sword art, god eater 2 and others we are awaiting confirmation will release.
Finally, because i simply enjoy playing games on the vita. It is a great system... if only Sony didnt drop it like yesterday's... it was a huge mistake for Sony to not have greenlighted that second Vita Uncharted.

I get to play japanese games on it. It is much more convenient for me to translate Vita games compared to ps3.

This.

PS 1 classics, remote play, good ports of classic titles(Duke Nukem 3d with dual analog controls, Minecraft), Indies and true Vita exclusives that show off the power of the system(uncharted, Killzone, Tearaway, Gravity Rush etc). I do wish it had more exclusives games designed for it though but that has gone out the window now. They could at least port some classic arcade titles over like Snow Bros and even a Doom port would be awesome as the smart phone version sucks due to touch controls. Also the OLED screen... Damn...

because one day it will be worth 4x retail value of how rare and retro it i lol.

It basically became my portable nostalgia machine. More half of my 32GB just consist of ps1 classics and psp games then add Remakes like ffx, x2 and persona4. Xp kinda dissappointed that Zone of Ender HD for the vita didn't grt released.

answered in on the first response 

lol, are you serious?
-it's an amazing system with more games realeased and coming out than i can afford to buy
-has an amazing screen, confortable to play for hours despite it's size.
-good battery life for me
-psx and psp digital games compatible

i get to play most of my favourite IPs on that system, it's a jrpg heaven!

why would i get rid of it at all? it has become more than i could hope for when i preordered mine