In Juliet's reply, she says she'd love to have a lavish dinner. Because the sales from Izzy Bickerstaff Goes to War are so good, she insists that she pay. Juliet includes a postscript insisting that she didn't throw the book at the audience; she aimed for the elocution mistress but missed.
The good sales figures from Juliet's book indicate that she's already successful in her writing career, even though her work thus far has been under this name. This again sets up how independent Juliet is.