In order to compete with "Audible" which is the most popular name in this business. Google Play have now added new features to their "Audio Book" that was first launched in January and available to Android & iOS.
For someone who listens to audio books here are the exciting features for them.
Bookmark Tool:
It allow users to save certain parts or quotes to access them later.
Resume Tool:
It allows you to playback to the beginning of a word or sentence.
Fast / Slow Tool:
It allows you to adjust the audio speed books. You can fast speed the audio to three times or you can also slow speed the audio to 0.5 times.
Google Assistant:
It allows you to add audio books to your Google Assistant routine.
I suppose these features should have been added already by Google at the first launch only but however better late than ever.