I agree with jwms that the two go together, and I don't quite understand the distinction between the two. Found objects rarely fit the need perfectly so need to be crafted (modified, hacked) to work. Some raw materials are usually part of the process of modifying found objects. In the examples above, paper is central to the "crafty" solution, evoking the terms handicraft, or "arts and crafts." But sometimes wood or metal is a better choice than paper. If wood or metal is required, it it still "crafty?" Is repurposing a DVD as a diffraction grating more "crafty" or "found object?" Because it requires only scissors, it seems more like craft. Is the DVD more like a raw material or a found object? If the paper used is from an old cardboard box, is that a found object or craft material?

To optimize community engagement, specialized tools and hard to find materials should be avoided. That way more people can participate successfully. So paper craft is always a good solution. But some things are hard to make from paper, so found objects (boxes, clips, ties, tubes, lasers, DVDs, webcams) are crucial parts of the solution. Sometimes a single found object can eliminate the need for lots of crafting and supplies (it's easier to build a soda bottle camera rig than to craft one out of sheet metal).

A special aesthetic is satisfied when the found objects are found lying around and have little other value. This is the ultimate repurposing. When the found objects must be purchased, they are really raw materials, just like the fancy paper Mathew uses. If the purchased objects are repurposed, that is cool, but they might still be more like raw materials.

There might not be a good answer to this question. It depends on the project and on the community you want to engage in it.