Maps communicate powerful messages about the world, but usually they're so small that they distance us rather than bring us closer.  A change in scale, and the opportunity to walk on the earth it portrays instead of facing the image on a wall, creates a far more visceral interaction with the material.  We can argue the advantages of the Peters projection over the venerable Mercator, but don't feel the details should obscure the opportunity.  A large map of any projection offers a chance to demonstrate all kinds of information about different countries comparatively, stacking coins for example to demonstrate relative GDP or average income, or having students plan and execute virtual trips, or letting them study and talk about the countries they come from or visit. Too often, we encounter people with no clue about the world beyond their own doorstep: the big map is a visceral way to connect them to a larger reality and different perspectives.