Most interviews I've done have expected me to write code on a whiteboard. This is pretty unnatural for me. I'm a very fast typist, so it's frustratingly slow to have to draw letters manually on the whiteboard.
It's also important to see how reliant people are on their tools.
I like to measure a carpenter's skill based on whether they can build a nice looking bookshelf with just a pocket knife said no one ever.
This could be an issue with really fancy IDE features, but there's a world of difference between a whiteboard and an IDE - namely, a text editor and an interpreter/compiler.