For now iTunes still dominates the podcasting ecosystem. It is estimated that they have around 60-65% of the market.It is therefore critical that you are showing up there in your category. The comparison is like saying: Only rank your website for Bing and don’t bother doing it for Google?Bing is an important search engine however we all know that Google owns most of the market and therefore its relevance is still the highest. Same goes for iTunes.
Its best to focus your marketing attention to the place where most of the market is residing and in this case of podcasts, it’s iTunes.