Jon Voge gives us a use case for Fabric SQL Databases:
Until recently, Fabric has allowed us to choose between Lakehouses and Warehouses as a backend. For write-back use cases, neither are ideal.
- The SQL Endpoint of Lakehouses are Read-Only, making writes from Power Apps impossible.
- While the SQL Endpoint of Warehouses are write-enabled, they do not support enforced Primary Keys, which are a hard requirement for Power Apps to be able to write directly to a data source.
Jon briefly describes two mechanisms people used and then how you can do this more effectively with a Fabric SQL Database. Based on the article, it seems that you could probably still do the same with an Azure SQL Database, though I suppose handling the managed identity could be an issue.