I remember seeing this
old post by Don Nguyen from 2014 in one of my blade forum searches. Don has not been on the forums since before I joined, but I recently came across a
youtube video by him about grinding bevels and he did not use a surface grinder, for whatever that's worth.
I think it is possible to get a good start on the bevels with an SGA as shown in the thread linked above, but I have no personal experience with it. A full flat grind on any blade that does not have a straight cutting edge seems like a mathematical impossibility to me anyway, in the sense that you cannot have two planes intersect in anything but a straight line. A nakiri is close, but if you look at Don Nguyen's knife on the SGA, you can see how this might be helpful for many knives that do not have too much belly. But you'll still have to finish the grind by hand. The other thing that I cannot quite wrap my head around is how to do the second side of the knife because I don't really know whether the bevel or the remaining flat area would end up flat against the chuck. Maybe that's not an issue at all, I don't know.
I'm a hobbyist, and even though I've made a few knives, I still consider myself very much a newbie at this. If you gave me a surface grinder today, I would not use it to grind bevels even if it eliminated 90% of the work. Part of it is because I want to get better at grinding and want to practice as much as I can. The bigger part is probably because the work that the SGA could eliminate is actually fun to me. I do most of my work on a computer so working on stuff with my hands and creating something tangible is very rewarding to me. Well, I am digressing, so as a fellow newbie I'll end this post with a famous quote in the field of computer science that may or may not be relevant to this discussion:
Premature optimization is the root of all evil.