The signal that you've outgrown Excel is repetition: every month you copy new data into the same file, fix the same formulas and rebuild the same charts.
Power BI's core value is the refresh: you design the transformation and the report once, then new data flows through automatically. For engineers, the learning curve has three steps — Power Query (cleaning), the data model (relationships), and a handful of DAX measures.
You do not need to be a programmer. If you can write nested Excel formulas, you can learn enough DAX in a few weeks to build management-grade dashboards.
For project teams specifically, the highest-value build is a planned-vs-actual S-curve fed by P6 exports — the exact project we build in Power BI for Construction and Project Controls.