Braque's Shelf Paper

I always thought that if I could own two paintings, I would want a Braque and a Chardin, but perhaps if I had enormous walls and a billion [some currency] my ambitions would adjust to fit the new parameters.

There's a Braque retrospective in Paris right now, without--why?--the usual blockbuster lines. I got stuck at the beginning of Cubism, or rather the papiers collés or collages. The wall text explains how Braque went past a hardware store (une droguerie, what is this in English?) one day and noticed rolls of wallpaper, or maybe shelf paper, in the window, rolls with flowers and so forth, but one that imitated wood grain and even had faux mouldings round the edge. He bought a roll of the wood grain stuff.

Back home he cut squarish pieces from the roll and stuck the pieces on a sheet of white paper; then he took a piece of charcoal and filled the white space. He connected the squares of wallpaper with his own designs. He also wrote some letters and words, like BAR or RHUM. Braque said that the letters would confuse people about the space because letters don't exist in space the way things--guitars and so forth--do.

I've often wondered why contemporary artists incorporate writing in/on paintings--what magic words work--and this seemed to provide me with the start of a response.