Ideally you would be able to order with your firmware of preference loaded. Think the point is not that Android should be eliminated but that a Linux build should be included - which is exactly what Khadas is working on. Its not that easy though.
Reading on the arch arm site (they probably best overall Linux arm support) it looks like the 905 chipset is still in the process of being supported by the mainline kernel. The base support was added a few releases back (mainline linux releases a new version every 10 weeks or so) but mainline support for usb and networking is still a work in process. Not everything will be there for 4.10, maybe 4.11... Unless someone reverse engineers drivers for the Mali 450 we are going to need to use a binary blob for it (not great, but not the end of the world either).
Why is all this important? If you want to create an internet facing box you want to use the latest kernel & user space. This will tend to include the latest security fixes, optimizations, bug fixes & new features. The kernel the Vim uses now is no longer supported by mainline - impacting android too. Meaning no automatic security fixes - its already missing years of optimizations, bug fixes & features. Someone could port them, but it does not happen for free as part of the Linux development process.