Azure Analysis Services provides enterprise-grade data modelling in the cloud and easily integrates with Power BI on the front-end. It is a fully managed platform as a service (PaaS), integrated with Azure data platform services. _ _
A Data Warehouse provides a dedicated environment separate from operational or transactional systems and is specifically designed for analytical-reporting, ad-hoc queries, data mining and decision-support. _
Power BI has many native visuals to choose from and there are also many custom visuals available from the office store. However, there are times when your specific visualisation needs are not met by any of the native of custom visuals.