There is a clear line between functionality available in the free Viewer and in the full product. The Viewer allows you to explore existing configurations, with the only changes allowed in a view being switching fields, e.g. Bar view Split, in order to allow you to pick different fields; you might have a different field for different years of sales figures, for example.

Changes which are clearly related to publishing and configuration rather than navigation are not permitted in the Viewer. For example, configuring a view title, changing colours, or setting decimal places.

There may be cases where we allow configuration settings in the Viewer, either because they are ambiguous in this regard, or because we haven't been entirely ruthless. But these principles mean you can't change the scale/axes in the Viewer.