Good thing is that any theme/extension can change the font of the Height extension just by inserting the quoted lines. This makes it easier to customize Height. I use Roboto, because I use that for the other windows, as I find it easier to read than FG's default font.
For the Height Extension I agree that Roboto is a bit too thin, so I might change it later on. But the big blobby letters used by default don't look so good and read so easily either. It doesn't matter so much for Height anyway, because it's not something you need to read a lot.

