On smart filters, I agree that it makes sense to have to look at the doc to know how it works. But I do think that the option is quite hidden away, such that those that would want it (here, me), don’t even know it exists in the first place. The filter (and smart filter) widget could for example be added to the search tab, as a kind of advanced search? It could combine well with the current search functionality.
On creating smart playlists, maybe I’m blind but I cannot find the playlist screen you mention. The only way I found to create one is to follow these steps and save the filter as a smart playlist: [Wiki] Smart filters
About playlists, the trouble was that I couldn’t find the playlist I just created at first, since it doesn’t appear in the Home tab where I was expecting it. I had to go to the search tab to find it again and favourite it. Would it make sense to add Playlists as an available shortcut for the Home tab?