Intentional indeed. It is GNU Unifont - a 973KiB file that covers practically all of Unicode. In a bitmap font, platform independent, self contained, small. Practically all that SolveSpace strives to be.
https://www.unifoundry.com/unifont/index.html
Perhaps I've been using computers for too long but I actually like the non anti-aliased "sharp" and "pixely" look :-)
Pixelated can sometimes look okay on screens it was designed for. But I think the pixelated look improves with hinting that helps snap it to stroke widths, rather than randomly jumping between 1 and 2 pixels depending on how it happened to line up with the pixel grid.
This is what it looks like on my screen: https://imgur.com/a/YeAdiXC
A good pixel font would be a vast improvement over this, though I'd still prefer something that scales well (and respects the DPI of my screen, and isn't too small compared to the menu font...).