If you like something, but want it at a lower price, then you can sell the puts. And if the price doesn't come down, then you made out on the premium.
Can play it similarly to the upside too when own something whose valuation is getting rich. Sell the upside calls, and if it keeps going up, then you're selling a stock with a high valuation, if it doesn't keep going up, you again made out on the premium.
I don't really know if I'm doing that well with it, or even how well one can really do using such a strategy, but the rationale seems to make sense.