Any skier with good technique can make anything work. But it's really, and I mean really sweet when you find planks that are really in tune with you. You're unlikely to recognize this if you don't demo.
I agree. When I first demo'd skis I was amazed at how different some of the skis performed and reacted (even within the same category and with similar profiles). Sure I could ski any of the skis I tried, but being able to zero in on the ones that really impressed is the whole point and makes a big difference in the long run.