If there is powder, avoid it and let the experienced riders enjoy it!
All kidding aside, a few inches is great to learn on. Less pain when you fall and smoother runs. As people have already pointed out though, powder gets chopped up fast! This creates bumps and patches of hardpacked because the underlying snow gets exposed after the powder is scraped off. Riding in this scenario becomes harder.
I saw another good tip in here. I found that on easier runs, like blues, the sides are untouched. Pow gets pushed to the sides so some good riding can be found away from the middle of the runs.
However, when powder gets deep, it's actually a lot harder to ride than a groomed run. You have to worry about float, speed, and it handles totally different. If you venture into deeper pow, do not slow way down or stop. You'll sink haha. I learned that the hard way.