Below is the comparison table between Power BI and SSRS.
| Basis For Comparison | Power BI | SSRS |
| Definition | Power bi stands for power business intelligence which is the product of Microsoft. Used for analysis and generating the reports from the cloud as well as server | SSRS stands for SQL server reporting services, it is also a product of Microsoft. Used for analysis of data and generating reports on server-based data. |
| History | Power bi report server is first introduced in 2017. | SSRS was first introduced in 2004. |
| The Implementation | It is used to generate cloud-based reports as well as server-based reports | Only used for generating the server-based reports. |
| Benefits | Easy to use due to enriched graphical component | Drill down capability is more. |
| Accessibility | Can be used through the web, mobile app, and desktop | The only access to web and desktop |
| License | It is free for use. | It is paid tool. |
| Component | It is HTML 5 open source app-enabled and cloud-enabled SAAS. | SSRS is an enterprise visualization tool based on old technology. |
| Learning Curve | Power bi is a graphical tool so through drag and drop you can complete your but its internal process is hiding so that you can’t understand how it process internally. | In SSRS developer has to do all the coding and designing of the report so the developer has a better picture of the process. |
| Usage | It is easier to use because of the rich graphical component | Less user-friendly |
| Data Dependency | Can deal with structure and unstructured the data | Can work with structure and semi-structure of data. |
| Occurrence | In the IT market power BI is emerging and replacing SSRS | Till now SSRS has a lot of presence but now power bi has more presence. |
Conclusion
The choice between Power BI and SSRS will likely be straightforward and likely driven by requirements. If your organization only uses paginated reports on-premises, you will decide that SSRS is a more cost-effective option. On the other side if you have the need to render interactive or analytical reports on-premises, or you already have SQL Server Enterprise Edition with Software Assurance, then PBIRS will likely be your preferred choice. There are no circumstances that I can think of where both Power BI and SSRS will be advisable, if you have PBIRS, you have everything that SSRS offers and more. But yes definitely it will have some more cost-effectiveness.
Ref: https://www.educba.com/power-bi-vs-ssrs/