Easy to customize dashboards, easy access via SSIS or SQL Server Management Studio (SSMS), many options in Reporting Viewer; great support from MSFT team - they really care about your success! I wish we could easily set up our own reports directly through Excel instead of having so much "behind" code that is not fully documented/easy enough as it would be if built into Power BI itself? But this does mean you have more flexibility at runtime than when using Visual studio tools only but also requires some effort upfront with coding etc..
Maybe just make them build out PBIs themselves then offer those too without building custom solutions ourselves which was what i did initially before switching over completely?!