The platform won't host podcasts directly. Spotify can make new episodes of your podcast available as soon as you upload them to your aggregator or host. All you need to do is provide Spotify with your podcast's RSS feed, much like you would when adding your show to Apple Podcasts or other services.
The Spotify for Podcasters program is in beta, as the company says it hasn't yet "had a chance to build things we know you need and want." It is, however, promising those who add their shows to the platform access to stats (updated daily) on factors including how well your episodes are performing, audience demographics, followers, listener locations and engagement.
A major concern for podcasters (and all creators, really) is reaching an audience. Having their shows on a platform with more than 180 million users should help in that regard, and in-depth analytics should help them better understand who's checking out their podcasts. As for Spotify's end of the deal, the opportunity to build up its content library even further can only be a positive.