At Amplify 2016, Jeff Frye made a good point. They use GP’s MAPI functionality for email, they like some of the MAPI features over GP’s Exchange options. You do have to log in a lot with the Exchange option. But if you do that, you’re stuck with 32 bit office which means that you can use 64 bit Excel for analysis, Power BI, etc. This is just a mess so Steve put up a suggestion to fix it. Go to MS Connect and vote for this!
The lack of 64 bit Outlook support prevents us from implementing and using Power BI and other Excel tools | Microsoft Connect