Isn't It Redundant For GOP Candidates To Advertise On Fox News?

As the Republican primary contests approach, Advertising Age reports that Fox News stands to benefit from candidates buying airtime in hopes of reaching conservative voters. In fact, Rick Perry recently made headlines when his team purchased $1 million worth of ad time on Fox.

From Ad Age:

Mr. Perry's big buy seems to have already put Fox News ahead of its pace in the last presidential election season. National ad buys by presidential candidates or party committees on Fox News were relatively small during the 2008 campaign cycle, amounting to less than $1 million according to Kantar Media, and local broadcast affiliates will remain the top spending avenue for most political campaigns. But Fox News has surged in popularity during the Obama presidency, and executives say political ad spending is surging, too.

But here's the riddle: Given how Fox News already showers candidates with free airtime as well as always-friendly coverage (which in turn double as de facto campaign contributions), wouldn't Republicans be better off spending their money with other media outlets. Because isn't it redundant for Republicans to advertise on Fox News when Rupert Murdoch's channel already advertises Republicans for free?