Podcast players without server-side crawling can get really annoying when you're subscribed to more than just a handful of feeds.
When I was using Downcast on iOS refreshing all feeds took ages and a lot of traffic (some feeds with a lot of episodes can be more than 500 kB, that adds up when you're subscribed to 50 feeds) and since the refresh wasn't even threaded all it took was a single slow server to block the whole refresh.
Now in Overcast (which does server-side crawling) the refresh is instant and I can even get immediate notifications about new episodes.
I used to be rage against the serverside ("ugh it takes so long to refresh when I know there's an episode out!") until I realised that of my 20 or so podcasts I subscribe to almost all 20 of them have their entire back catalogue in their RSS feed
Serverside crawling means your app just needs to grab whatever's different instead of downloading 20 RSS feeds every few minutes/hours. Definitely a bandwidth saver
When I was using Downcast on iOS refreshing all feeds took ages and a lot of traffic (some feeds with a lot of episodes can be more than 500 kB, that adds up when you're subscribed to 50 feeds) and since the refresh wasn't even threaded all it took was a single slow server to block the whole refresh.
Now in Overcast (which does server-side crawling) the refresh is instant and I can even get immediate notifications about new episodes.