To think that flaps increases lift and drag by increasing the wings camber is ignoring what is really causing the increase in lift and drag. When flaps are deployed the angle of attack goes up on that section of wing (usually the inward section) because lowering the trailing edge of the wing lowers the reference point where the cord line is measured. Because this section of wing has a higher angle of attack than the outward section it is the first to stall leaving the outward section still flying. And because this outward section has ailerons control is maintained. Just like you said it reduces tip stall. When you decide to land you don’t need extra lift but the ability to fly slow and still maintain control will come in handy.