In Puzzle 13, you are in a preendgame where you need to bingo. There is one good bingo line available and a few other bingo lines available. The key to this pre-endgame is endgame timing: you want to play enough tiles so your opponent can’t get a good scoring play, but you don’t want to play too many tiles or your leave will be too weak and your opponent will have a good idea of which line to block. Because of your opponent’s scoring plays, you don’t want to play LUG or LUGE at 7h.
Opponent’s plays such as OVA 15g or LIFE 9b score enough points that they will outscore your bingo: if your opponent scores well and leaves tiles in the bag, you won’t be able to win. Likewise by playing ARGUED you minimize your bingo chances by drawing 6 random tiles and give your opponent enough information about your rack that he or she can block your best bingo chances by playing a 1-in-the-bag preendgame.
By playing LUGED 7h, you create multiple bingo lines without letting your opponent score too well by playing off 2 tiles while keeping a good leave and leaving your opponent unsure about which bingo line to block. Ditching the E is reasonable since there are only 7 in the bag and 4 Es are left in the pool.