I found the GBS-8220 itself to fiddly, but 'more or less' does the job; the MiST doesn't work on 'any' of my TVs without assistance (sigh), so it needs the GBS-8220 to work 'at all', which is a shame. The GBS-8220 itself tends to have the issues noted above.. centering, or wrapping, or others.
So sometimes I'd like upscaling (and its fiddly), or other times I just want an image that works at all (MiST), without all the fiddly.
So the use case for me (maybe unique?
is something less fiddly; I envisioned it as a simple small little board .. VGA in, VGA out, the ISP or JTAG flash header, and some GPIO and/or buttons for controlling config settings. ie: A VGA to VGA pass through, that cleans up a otherwise goofy VGA signal.
So for MiST ue case.. I coudl plug it into MiST like a little dongle, and get it to work easy. For upscaling case, the GBS-8220 is goofy, could clean it up.
I have heard tale of some goofy things like hooking up an r-pi to it, but thats annoying. I'm trying to simplify my setup, since I've found complex/goofy/fidgety is offputing, and time is so tight.. want to make life easier
A better option is to redo or patch the firmware on the GBS-8220, to emit more useful signals; I've heard some action on that front, but didn't find any reports of real progress or releases, but it was sort of hard to find at the time I looked.
As someone who does a lot of electronics hobbyest hacking (I've made my own console/computer from scratch!), its a doable and tempting hack of a project. But also probably more work than its worth because as you say.. there are options