Dataflows and Datasets are some great new features that you want to leverage moving forward. They are mighty and enable several great features that add resiliency, ease of access, lineage, auto-documentation, and several other benefits that enhances ROI to each business unit.
What are Power BI Dataflows? Power BI Dataflows allow you to define individual tables that can be used in different data models out in Power BI. Some examples would be a Product, Employee, Date, or Transactions table that you would want to use the same information in different data models. Dataflows allow you to load the data from the source system out into the Power BI service a single time, transform the data once, and then consume the data many times.
Dr Dataflow himself, Matthew Roche explain the difference between Power BI Dataflowsand Power Platform Dataflowsin this great video that he has over at BI Polar.
What are Datasets? Datasets are a combination of tables, joins, and measures that can be used to build out Power BI reports. Any time you build out a Power BI report, you are building a dataset. Radacad has a great article on what is a Dataset and how can you use them to improve your reporting and performance.
https://radacad.com/power-bi-shared-datasets-what-is-it-how-does-it-work-and-why-should-you-care
Why should you use a common Dataset? Excelerator BI published an excellent article over a year ago about the value of having a "Golden Dataset" with an easy to understand examples. Check out the first two sections in this blog ("The Problem- Too Many Data Models" and "What is the Golden Dataset"). The rest of the blog provides a detailed technical guide that is nearly 100% out of date and should be ignored.
https://exceleratorbi.com.au/new-power-bi-reports-golden-dataset/
What are Promoted & Certified Datasets? Once you start to build out datasets that can be used for multiple reports, you can category the dataset as either "Promoted" or "Certified". Best Practice is to mark a dataset that are used by a team or division as "Promoted" and any dataset used by the enterprise as "Certified".
Our friends over at Guy in a Cubehave a great video about Shared & Certified datasets.