Even though I like it, it’s not really anything significant in terms of openness, it’s selling point is really its card form factor and the ethical goals of the project re supply chain requirements.
The actual device itself is an old Allwinner SOC with Mali 450 graphics. Until recently, this would have necessitated either software rendering or running a blob.
Thankfully, the lima driver efforts have come to fruition, and there are now open drivers available for Mali 450 on linux, albeit in early development and provided your distro provides a new enough kernel and mesa combo. Panfrost is a similar open driver for newer Mali GPUs as well
In terms of software openness, you would get the same results from many similar ARM boards (apart from PowerVR, and some early devices), and in some cases, such as the imx6 and imx8 or the Raspberry Pi, you would get a more open board (in terms of the provision of specifications and cooperation of the manufacturer) and a more mature open driver.
Having said that, I have backed it myself, as I really like the idea and want to encourage more projects like this, with privacy and ethical focuses, and that provide libre distros out of the box.