To me, this is also important. Let's be completely honest, writers love all the views, likes, and comments. We also love when we know our readers are enjoying what we create for them and for ourselves. We should always show our appreciation and interact with the people who are taking time to support us as writers. 

If you can't reply back to every comment, it's a good idea to thank them for their support in every book they are supporting in at least one chapter. 

It is never a good idea to ignore readers comments.

Be grateful towards your readers.