Meh. I've had many cars. Some with it and some w/o it. Most of the time when the light does come on you have maybe 3 washes left. I have always carried a spare bottle in my trunk.
Many low-end cars have a low fluid sensor...
I don't know where you're from, but around here, when it snows and the roads get all crappy, you're happy to know you're about to run out of windshield washer... Believe me.