i will ALWAYS buy a physical CD for the artists I Stan for. No questions asked. Every Britney and Carrie Underwood album I have physically.
I would much rather have a physical CD, but a lot of times it's more of a money and availability issue. When 21 came out, the only stores around that had the album were at places like Barnes & Noble (which were 20-30 mins away). I'm not about to go out and buy a CD that's out of my way, and even pay that extra few bucks just because it's at a retailer.
That's why IChunes gets my money 8 out of 10 times. It's easier, cheaper, and I can buy the album an hour early before retailers put it out on release dates.