Both, of course.
The ideal CI crossword puzzle is a reading activity, not a decoding activity. Even better, it is wrapped inside an exciting group activity. Here are the crossword games that I created as post-reading activities to chapters 1-10 of my TPRS novel, Superburguesas. Students work in groups of three. Each group has one copy of the puzzle (without clues). The clues are taped outside against the wall, in the hallway.
Each group member is assigned one job (s/he can switch jobs with a teammate mid-game, but only one student at a time can be doing each job). One student, the corredor, goes outside to read the clues. The escritor stays inside guarding their clue sheet (one per team) and writes the answers. The last student is the lector, which gives him or her the right to consult the novel. I always keep the novels in a separate part of the class to make the game a little more exciting. These crossword games are meant to be short… just a quick burst of movement to keep the blood flowing.
Check out my Superburguesas homepage to see the other free activities that I have posted to teach my TPRS novel.
(Click on the images to get a larger image, then right click to download the image)