So a bit of research reveals that they're not really the same at all:
Weyermann sells the same product as CaraFoam in the US and Canada, and as CaraPils everywhere else because Briess got the US & Canada Trademark on "CaraPils" first.
Briess CaraPils is a very light (1.5°L) true crystal malt that hasn't been roasted enough to develop the color and flavor usually associated with crystal malts. No diastatic power. Recommended usage of up to 5% of the grist.
Weyermann CaraFoam (aka CaraPils elsewhere) is NOT a crystal malt. It's slightly darker (1.5-3°L). Diastatic power of about 35-45° Litner (just on the verge of being able to convert itself). Recommended usage is up to 40% of grist.