Aside from changing the default font name type, in GS-Calc 21.2 you also change its size:
Changing that size affects all displayed worksheets, tables, control panes/views and elements, etc. that use the default font. For example, setting the size to 14pt makes the sample.gsc look like below:
The ability to modify the default font size can be useful especially if
(1) you switch to a font family/type that appears smaller for the default 10pt or
(2) if you simply can’t easily read the 10pt text and the Zoom function is not sufficient as it is defined on the per-sheet basis and doesn’t scale the control panes with notes, search results, pivot tables, simulations and so on.