Hi @shawnaby ,
Could you please share a bit more about your scenario?
Based on the issue that you mentioned, I think you have some misunderstanding in CDS and PowerApps Apps (Canvas app & Model-Driven app).
The Common Data Service is actually a built-in database service within PowerApps, which lets you securely store and manage data that's used by business applications. Data within Common Data Service is stored within a set of entities.
Please check the following article for more details:
https://docs.microsoft.com/en-us/powerapps/maker/common-data-service/data-platform-intro
The PowerApps is actually a SaaS (Software as a service) product, which is a suite of apps, services, connectors and data platform that provides a rapid application development environment to build custom apps for your business needs. Using Power Apps, you can quickly build custom business apps that connect to your business data stored either in the underlying data platform (Common Data Service) or in various online and on-premises data sources (SharePoint, Excel, Office 365, Dynamics 365, SQL Server, and so on).
Please refer to the following article for more details:
https://docs.microsoft.com/en-us/powerapps/powerapps-overview
There are two apps type supported in PowerApps -- Canvas App & Model-Driven App. The Canvas app could connect different data sources, including Online data source (e.g. Common Data Service, SP List Online, ...) or On-premises data source (SQL Server, MySQL, ...). But the Model-Driven app could only connect to Common Data Service.
Yes, you are right -- CDS can technically do everything Sharepoint can do. The canvas app connects to CDS would have faster data processing speed that that connect to SharePoint list. And the Delegable functions or operators supported in CDS are more than that in SharePoint:
Delegable functions in SharePoint
Delegable functions in CDS
Best regards,