For visualizations including Bar charts, Cross tables, Scatter plots, Waterfall charts, Combination charts and Line charts, the font settings in Properties > Fonts for X-axis (or Category-axis) and Y-axis (or Value-axis) are noted as "printing only" in versions prior to 10.7, and as "printing, only for deprecated export" for 10.7 and later versions. For example:
If you change the font here, the only way to view the changed font is using deprecated export/printing (including 7.9 PDF export, 7.11 Microsoft PowerPoint export and 7.11 Print).
That is to say, this change could not be reflected on the visualizations, or current export/printing features.