BI tools (Power BI or Tableau) not just for visualization

Since there is no feature to simply add comments only  I use the Q&A feature to share my thoughts. Apologies in advance.

Simply stating BI tools as useful for visualization only is a great disserve to their true capabilities that goes well beyond visualizing!
I use both tools mentioned (mostly Power BI) and I can tell you visualization is the last stage in building a self service solution. Put it simply, everything you can do in Excel can be done in Power BI (calculations, modeling, analysis, ETL, etc.) and much more. Using DAX & M in Power BI is like running Excel on steroids!

By the way, today's Excel uses the same technology as found in Power BI (and why not? Both tools share the same parent! :-) )