@Barak Schriger This only works for titles. It does not allow you to update formatting for all dashboard fields at once as it should do. The horizontal and vertical axis labels still need to be manually reformatted one by one. If you select all widgets and change the font/size/color, the axis label styles always remain unchanged.
If you multi-select the charts you want to modify you can use the "Widget Styling" section to modify all the fonts within the charts using 'Body Text' (excluding chart series labels) - ex. legend, axis labels, axis titles
If you multi-select the charts you want to modify and you want to modify a single attribute like the horizontal axis label, you can do that from the edit menu as well
Hope this helps and let me know if you have any additional questions.