Why are bed bugs attracted to Carbon Dioxide?
It's nothing to do with what they breath, they're attracted to carbon dioxide because it's generally a good indication of the presence of a larger organism (such as a person) so they're simply following the "scent" (for want of a better euphemism) to their food (in this case you, or whoever happens to be in the bed), the traps in your links just take advantage of this to trap and kill them.