Actually, you don't need to use this to refer to the data. Just the name of the variable would do; is it some convention that is universally followed or it's just that you've gotten used to it? Can't see any other 'practical' use (as in it's a must to use this) other than returning by reference.
BTW, you guys coded the Knight's Tour anytime? Basically, you need to return to the square on the chessboard (specified arbitrarily) that you started on; after covering every square ONLY once. And of course, you move like a knight does in a chess game. I haven't actually coded it but I thought about the algo in a lecture I was getting terribly bored in.