Because the newspaper regularly needs to discuss numbers on the order of billions, and it's nice to save a couple of syllables over "thousand million" every tim

Because the newspaper regularly needs to discuss numbers on the order of billions, and it's nice to save a couple of syllables over "thousand million" every time. The newspaper only occasionally discusses 10^12s (mostly in the context of how much debt the US is in, go figure) and "trillion" is fine for that. (The long scale trillion is 10^18, a useless sort of number.) Larger numbers rarely need to be discussed outside contexts where you'd use scientific notation anyway.