There's nothing I couldn't ride on the old bike that I can ride on the new one. Even when my 'other' bike was a 6"/6" Giant Reign, that bike didn't make too many things rideable that weren't on a hardtail. (Granted, I'd never chairlift my hardtail or roll off 3' drops with it...)
The difference is that if it's a rough day of climbing over rocks, dropping 2' logs on the trail, cornering at 20-30 mph, that sort of thing, it's great to have the travel and the brakes. It's a joy to spin and climb in the seat without crouching for two hours, and it makes it easier and more enjoyable to go for a long ride. It's great to brake deeper, corner a little harder and have the wheels touch the ground a little more.
It also depends where you live. North Shore riding on a hardtail would be pure punishment!