https://www.gamespot.com/articles/xbox-one-backwards-compatibility-is-super-popular-/1100-6458692/

When Microsoft announced that the Xbox One would play Xbox 360 games through backwards compatibility, some wondered how popular the feature might be. As it turns out, it's very popular. Microsoft announced today that Xbox One players have collectively logged almost 1 billion hours playing Original Xbox and Xbox 360 games on Xbox One.

In June 2017, Microsoft announced that people had spent 508 million hours using backwards compatibility, so usage is only growing. According to Microsoft, around half of all Xbox One owners have used the feature. Some have questioned whether or not people actually use backwards compatibility, and of course they do.