Stream is a replacement for Office 365 Video, although currently the two coexist. Since Stream is being built from the ground up and doesn't rely on SharePoint as Office 365 Video does, it doesn't yet have all the same capabilities as Office 365 Video, as of writing this book. Microsoft's plan is to allow users to migrate, if they wish, in quarters one and two of 2018, then opt out of migration if they don't want to move, and eventually, everyone will be migrated once Stream is feature-complete.
Stream comes with enterprise versions of Office 365. If a business premium plan is the highest anyone in your organization has, you won't see it.
