I don't know, but I guess that the batter with baking soda and/or powder would be a bit lighter and fluffier, as the leavening agent reacts with the buttermilk. However, I don't know if merely milk will be acid enough for it to react.
Heston Blumenthal did puffed rice in his risotto episode. From what I can gather from the video, here's his way: 1.5 cups of cooked basmati rice (he cooked it for a little under 10 minutes) 1 tea spoon saffron (looked like something like that) Mix the saffron with the rice. Spread out evenly on a baking tray with parchment paper. Let it dry out in the oven for 1-2 hours at 60-70 C. Fry the rice at 190 C. It's done when it pops up to the surface. Put the rice on a piece of paper and let the excess oil drip off. Maybe you will have better luck with this one.