The main reason for adding a daily puzzle (or really the seeded RNG) is that part of the game loop is retrying the same seed to find the best lines for that map. Since all pieces are deterministic, we've found it fun to retry the same map to see if a different line works better. It also adds a competitive/multiplayer element to the game, rather than it just being for single player use.
I think both "play styles" make sense, we've just found it more fun to share with friends this way!