Why is there red lettering and a red seal on the 1953 five dollar bill?

Answer 1

Because it is a United States Note. Its worth a modest premium over face in average circulated condition, about $7 or $8 or so retail and up to $10-20 if nice and crisp.

US currency is mostly color coded. (There are some exceptions such as some of the WWII overprint notes and some of the early large-sized currency)

Green, which you see all the time today is a Federal Reserve Note

Blue means the note was a silver certificate and (up until the 1960s) you could redeem your note for silver dollars at the treasury

Red means the note was a United States Note

Yellow means that the note was a gold certificate and (up until 1933) you could redeem your note for gold at the treasury

Brown means that the note is a National Bank Note

The differences between the Federal Reserve, National Bank Note and United States notes are the issuing authority was either the Fed, private banks or the US treasury itself.