Ease-of-use, intuitive, shallow learning curve, no need to go through documentation once a user if familiar with data visualisation and data analytics concepts. Possibility to enter aggregated data along with their dimensions with with ease as opposed to Excel sheets. Data visualisation design with lightning speed when compared to a rigid chart design in Excel and intuitive data discovery devoid of technical burden.

Perhaps I'm missing a facility for technically advanced users to import raw data in either tabular form in its aggregated form.