True. But if you have a large amount of shares of any stock and the stock trades in a very narrow range or stays flat for long periods of time, writing covered calls is a good way to generate income and keep the shares for dividend purposes. This is what I do for KFT and some others.
With a dividend stock like this, it's almost preferable that it the stock price is steady. Then you can collect your 3.7% and not worry about losing principal. I've never lost any sleep over my KFT stock.