The purpose was to show useful prayer times for those who are searching Google for Islamic, Jewish or other prayer times in the Google search results. Here is a screen shot of how it looked when it first launched:
It came up for searches such as prayer times in city or searches that would return prayer times. In my story from a year ago, I get into the complexities behind showing such search results. Google did not remove it because of those complexities, rather it was removed because barely anyone implemented it.
Google told us:
Users can still search for prayer times on Google and find results from local sites, but we weren’t seeing much implementation of prayer times rich snippets, so we’ve removed it (apologies to webmasters who took some time to implement it) and are focusing our resources on developing different kinds of structured information in rich snippets.
I am not sure if this is the only rich snippet to be decommissioned, I am following up with Google to find out.
Yes, you can still use Google to find web sites that have prayer times for specific religions but you won’t find any rich snippets on those search results – Google killed them.