That's not at all true. I've been a longboarder for 8 years now, and I have never once heard someone say that bearings don't matter for longboarders. They matter waaaaay more for us than they do for skateboarders.

The difference is this: impact bearings vs. precision bearings. Impact bearings are made for skateboarders, usually steel balls since they're tough. Precision bearings are made for speed skating, e.g. longboarding. They're made of materials like ceramic because they are hella smooth and roll forever. The downside, of course, is that they're brittle.

Ceramics have no place in the skateboarding world because they shatter when you start subjecting them to the shock of landing a trick down a 6-set. Longboarders don't care (aside from some of the advanced longboard dancers, but that's hardly the majority) because we want bearings that roll smooth and roll forever. Commuting is way easier when you have to kick 50% less. Furthermore, downhill bombers (those insane speed junkies -- mad respect though) sure as hell want fast bearings. If you're racing, you want the best gear.

So all in all, I have no idea where you're coming from, but I'm confident you have picked up some bad information somewhere along the line.