When the author says that "the computer is not so much a better pencil as a better eraser" $($lines $1-2),$ he most nearly means that

the computer is not as useful for writing as traditional writing tools.

the computer makes writers indecisive.

words stored on computer hard drives are not stable and may be erased.

the computer makes it easier to revise a written text.

the computer makes it easier to forge, plagiarize, and swindle.