I was surprised to learn that I wasn't using the favorite feature! I primarily browse HN through the Android app "Materialistic", which has a prominent "save"

I was surprised to learn that I wasn't using the favorite feature! I primarily browse HN through the Android app "Materialistic", which has a prominent "save" button at the top of each story. However, those saved stories (~1.1/week) aren't favorited. Just saved locally. Could this be part of why the feature seems so rarely used?