What does the reader learn about Dill in this chapter? Why does Lee mention this?

The reader learns that Dill has no home.

“Grandma says he hasn’t got a home—”

“Has too, he lives in Meridian.” “—he just gets passed around from relative to relative, and Miss Rachel keeps him every summer.”

This very brief passage gives us further insight into Dill's character, and once again reminds us that things are not always as they seem.