Even if you skips 90% of a 90 second ad, the advertiser still has 9 seconds to get a pitch in. Sometimes in advertising, just reminding the users you exist is enough. If you hear "Dave's Pizza" twelve times before going to the grocery store, then you're much more likely to subconsciously grab one if you see them one in the freezer.

Podcast advertisers often fall into a category of product where name recognition is important. They are okay knowing that most of us skip the ads because they know the audience will hear the name before they have a chance to skip the ad.