Not for me. Any time that I'm not cleaning brushes is wasted in correcting poor control and second-guessing my decisions. crtl-z, stroke, crtl-z, stroke, crtl-z, stroke... For sketching and frankensteining sure. So, great for concept artist, not so great for illustration.
Here is what I consider to be great about digital art:
I only need a third of the space i'd need for a full traditional studio. Then again I only regret that I don't have the space. If I had the space I'd happily fill it with paints, bottles and shit. Now the problem is that none of these considerations will directly contribute to the quality of an illustration.
Anyhoo I finally got around to finishing an acrylic piece. It's just a doodle and not that great. I scanned it at very high res. When I finally had it in photoshop and zoomed, I almost wept. Gone was all the blurry digital marks. Every mark was where my hand had put it, as opposed to approximately where I put it. I spent minutes just enjoying the dust caught in the paint. Looking at where papergrain interacts with paintstrokes on paintstrokes. Donate money to the Pettersson-needs-a-studio-fund now!