Death by Spreadsheet | QGate
Spreadsheets are perfectly capable of managing a sales pipeline when the business is small and only a handful of people need to use them.
Things get more complicated as the team grows and different versions start circulating. Before long, no one knows which version to use, if the numbers can be trusted or whether someone broke the formula.
Dynamics 365 gives everyone the same view of the sales pipeline, with updates made against the same records and reporting based on consistent information. That becomes increasingly important when the rest of the business starts relying on those numbers too.