Why is it important that Jem Finch grows taller in the book?

The visual impact of Jem Finch growing taller in Harper Lee's "To Kill A Mockingbird" suggest he is growing in several different aspects of his life.  He is no longer a child, doing things a child would do.  He starts to consider people other than himself.  He starts to consider other people's feelings and ways of doing things.  Take the time he had to serve some time with Mrs. Dubose when he disparaged her camellia flower beds.  Initially, he would have rather eaten a dirt sandwich than read to her.  But by the time he had served his sentence, he came to understand a little better why she was the way she was.  His interaction with Reverend Sykes at Tom Robinson's trial shows his thinking is starting to mature.  So the fact he is getting taller serves as a visual reminder that Jem is changing in a lot of different ways.