I find podcasts and playlists pretty frustrating generally. But then I tend to want to listen to something fairly specific as opposed to more or less whatever as background; I've never been a big radio listener. I have used it for texts but that's very uncommon and directions can be hit and miss to make changes on the fly. It's definitely better than nothing but it's a far cru from a passenger doing that sort of thing for you.
I have the same use case but with very different results. “hotwords play my playlist foo” works for many values of foo with both google assistant and Siri. Ditto mapping, ditto sending texts.