In a major page 3 news story the Post told readers that Congress is considering an additional $1 billion appropriation for the Federal Emergency Management Agency in order to allow it to better deal with the range of natural disasters hitting the country. Since almost no one knows the size of the federal budget, and $1 billion is a huge number to most people, it is likely that many people will hugely exaggerate the importance of this spending to the deficit or their tax bill.
Polls regularly show that the public is grossly uninformed about the federal budget. This sort of reporting is the reason. It is very simple to report items as a share of total spending. Since this is the only way that the number is meaningful to readers ($1 billion is not meaningful to 99 percent of Post readers), there is no excuse not to present the information this way.