Whoa! At the Gartner BI Summit, they suggested we "Wave the white flag on using Excel for business intelligence". What breakthrough thinking! This is something we at Simba have seen for years. Many BI/OLAP vendors have come to us looking for an MDX Query Language solution for their OLAP/data warehousing products. We have found that a key driver for supporting the MDX Query Language was connectivity with Excel and specifically Excel Pivot Tables. Microsoft continues to invest heavily in the BI capabilities of Excel and having an MDX Provider for your OLAP/multi-dimensional data source allows Excel to connect natively. Native Excel connectivity is something we have now brought to Oracle OLAP cubes and we will even be at the Oracle Collaborate 10 conference next week where we have two sessions on showing users how to use Excel to connect to Oracle 11g database: http://www.simba.com/news/Simba-Provides-Free-Training-Connecting-Excel-PivotTables-to-Oracle-OLAP-at-COLLABORATE.htm.
Excel connectivity is a very important feature of any data source be it relational, multi-dimensional, ISAM, object-oriented, XML, etc. Excel can connect to anything that has an ODBC or an ODBO interface. Once someone can see how their data can be pulled live into Excel and how an Excel user can then get creative in their tool of choice, it becomes a very powerful reason to have an ODBC driver or ODBO provider.
You can read more about what Gartner is saying here: http://searchbusinessanalytics.techtarget.com/news/2240018042/Gartner-BI-Summit-Wave-the-white-flag-on-using-Excel-for-business-intelligence.