I've had some airplay with various projects, both ones I recorded/produced as well as my own bands.
It has done a lot for some, and absolutely nothing for others.. Not trying to be clever, but my take on it is that it adds to your presence and legitimacy as a muso, along with name recognition, but that one song getting a bit of airplay is worth far less than some solid live performances, touring and web presence - especially in the new age of the indi business model. If you have a hit, well then that's different... but what are the odds?
One of my most successful clients has never had ANY airplay, yet has sold Gold (25 000) between two albums in South Africa, and she has had 200 000+ views on Youtube of her live performances. But then, she works like a dog and has an audience more loyal than most. She has had a song on an American TV advert (YP.com) and has had tour invites from some major artists around the world incl Shawn Phillips and Lucinda Williams - all on the strength of great albums and killer live performance.
Then again, I've earned some nice money from a ballad I wrote a few years ago.
If you're asking if you should chase airplay with all your heart.. well, it depends on your genre and your level of commitment. If you're a rapper or a pop diva, spend your energy getting airplay. If you're a band, go tour if you can. If you have a manager etc, get them to push steadily until something comes of it. And avoid bribing DJs or paying for likes - word gets around :O)
Your Mileage May Vary, as they say :O)
Best of bacon, sorry, luck,
Ludwig