Of course, but I won't buy it day 1, I never buy hardware day 1, due to quick price drops (3DS, PS3), hardware problems (screen scratching, RROD) and lack of games. However I will buy a Vita a year down the line, when I may be able to for cheaper price or a good bundle, as well as games prices of titles I have missed earlier will go down I will get a Vita as long as it has games I want to play. So far I am interested in Uncharted, Hotshots Golf and LittleBigPlanet and maybe Gravity Daze if it gets good reviews.
As for owning a Smartphone, I do own a iPhone, and I play the occasional game on it, I actually think iOS games are more appropriate to play on the go. Before I never used to play games on the go, but with iPhone, and can play a quick game of Angry Birds or Doodle Jump while I am on the go. But most of the time, I use my iPhone to web browse or listen to music. As for why I would want a handheld like 3DS or Vita as I reckon iPhone games are more suitable for gaming on the go. Is because I mainly play handhelds at home, or when going out in a long journey, holidays, staying over in another place, long trips and etc. TO be honest I bet many people will say the same thing, there are so many DS's that sold, yet I barely see anyone playing DS outside, it just shows that many people use handhelds for the same reason I do.
And like one of the above posters has said, heavy gaming on a phone isn't good as I wouldn't want my phone battery to die, I rather play light games like Angry Birds on a phone for 5-15 mins than play a proper game and kill of all my battery life on my phone.