Havana is really big and, like any large city, also has districts that are simply residential areas. Places that are neither the city centre nor tourist hotspots, but where normal life takes place and you bump into locals and see things or buildings that are otherwise rare or non-existent.
Habana Barrio is of course also quieter than the city centre or Casco Viejo. It’s basically like another world. As I personally like to get to know places and cities from their authentic everyday side, I enjoyed wandering through Habana Barrio.
Go or not? If you have time, go for it. Otherwise I think there are too many other things to see in Havana.