Commenting from my experiences - yes you can connect XLS to data and use Power Pivot. Some of the bigger gaps with this approach are: (1) making / formatting reports that meets accounting/finance and C-Suite look & feel / formatting expectations; (2) maintaining the chart of accounts and reporting hierarchy (3) an audit trail of who did what and when. There are plenty of other "gaps" that XLS doesn't easily address.

Corporate Performance Mangement (CPM) technologies like Pigment address the finance team and other information consumer's requirements.

Recently I ran a workshop focusing on just the theme of Daniela's article. Take a read https://medium.com/illumination/cfos-dont-let-spreadsheets-become-your-sirens-c530d3fe6910

Thoughts??