Correct, and there never has been via the Ruby API.
Others have agreed and said so, and requested this be added to the Ruby API for many years.
Discussed in these forums in Feb of 2015 …
And again later that year in November of 2015 …
Officially requested in the official issue tracker in February of 2018 …
(… although it has been requested and logged long before even 2015.)
Note also discussion threads in this category and issue filed specifically for leader text object font access. (Please search and add comments. Ask to unlock threads if needed.)
Not with the Ruby API. There is actually no Sketchup::OptionsProvider instance yet implemented for the “DimensionOptions” (seen in the Model Info dialog.)
I just logged an issue for this (just in case it’s been overlooked) …
The SketchUp C API does actually have these methods to get and set dimension fonts, but last I heard from @thomthom, he said using the C API on a live model was unsafe.
So I can’t say if there are actually any workarounds.