Neither molten salt nor wind are zero at night. In fact, wind usually is higher at night than during the day.
Even if you're somewhere where the wind could give you 90% of your energy, you'll still need a reliable, baseline power source if you don't want everything to randomly shut down the other 10% of the time.
Wind + solar aren't as cheap as the LCOE makes it seem because you always have to pay for another source of power as baseline. If you added similar subsidies to natural gas it would be by far the cheapest energy source