Really depends on what the landscape looks like for the customer. Most people using PowerBI are not doing anything any different than what they are doing in Excel. It's just a lot fresher, easier to piece together sexy eye-candy reports and is totally integrated in the cloud with potentially your data. But, it's not ideally a centralized reporting solutions like MicroStrategy Server where you can fully ensure the 1,000 of Excel sheets in your clients business are all in one location, version controlled and not going to accidentally get deleted.

Outside of that, it's a cheap cost effective visualization tool that will help you tell a deep and meaningful story about your data. It helps answer questions that the business wants to know and it's not going to break the bank doing so.