I enjoy spoken word audio; drama, documentaries, comedy, a wide range and YouTube nowadays has a great selection of all sorts of stuff worth listening to but much of this content does not really require video streaming just audio streaming. Consider a panel debate about, say, climate change; one doesn't need to see video of people discussing it but simply hear the audio and as one hour of YouTube video will consume about 700MB of your mobile phone data but one hour of audio will consume only around 45MB then streaming just YouTube audio without video would be ideal.
Unfortunately YouTube does not permit this (premium accounts may?) but there is a great Android YouTube client called NewPipe which does, it has a "Play in the background" feature which just streams audio not video. NewPipe is an open source and free app. It is not available on Google Play but you can find it here:
