When Power BI functionality first came out for Excel, I was very excited. I still am. I always try to use it as much as I can even to prove simple points. I promote its usage wherever I can. As a techie I find it a great tool; am very fond of it. Others however, look at it from a slightly different perspective: Something that is trivial from my point of view, but entirely the opposite from a business user.
I was recently helping out a project manager build a dashboard of metrics for a client. Data was in Excel, imported from a couple of sources, she needed it mashed up and showcased with a wow factor. This was a chance for me to impress someone with Power BI. So I got her set up with Excel 2013 and all the Power BI add-ins. Then, I taught her to shape the data using Power Query, and build a model in Power Pivot, and finally put it out on a couple of Power View sheets. It wowed her! This was exactly that she had wanted to impress the client with – something additional apart from the services we were already giving them.