My guess is that the flat side provides a better surface for distributing pressure so long as the thing you are wrapping isn't a porcupine.

I think it's simpler than that. Bubble wrap the wrong way round means the only air cushioning is provided by the bubbles, and all the space between the bubbles is just a thin layer of plastic flat on the object that needs protection. Bubble wrap the right way round means the object is air-cushioned from the outside by both the bubbles themselves and the space between them (with the added bonus of the wrapping keeping a flatish outside surface).

Mine as well.

Imagine a small enough object, like a tip of a screwdriver, or a table's corner, touching an object wrapped bubbles out.

It simply makes contact with the object - here covered with only a very thin layer of plastic - between the bubbles, and given enough force, damages the object.

With bubbles inwards, it has to pierce or stretch the now airgapped layer of plastic first.

Even with multiple layers, bubbles inside give +1 airgapped layer.

Well, the most obvious thing would be that the airpockets created by in-between the bubbles _have to_ be on the inside next to the item, otherwise there is no air pockets at all, so obviously the bubbles most face inwards.

That's how I was thinking about it before this article at least.