Should they maybe use a different service for what is basically a pre-order? Maybe, but Kickstarter allows for some interesting features that I don't think others websites offers--such as stretch goals and different reward tiers.
Each episode will be sold with the "pay what you want" method, so they are implying that each episode of the podcast is worth spending money on. If you don't think that a podcast should be paid for, that's an entirely different issue. Those who pay $10 will have earlier access to each episodes, and are essentially paying 50 cents an episode.