I’ve lately seen the take that “Tron was disqualified for Oscar FX nomination because using a computer is cheating” but I think some nuance must be lost. I could imagine fully CGI shots weren’t counted as FX shots. Maybe you know something that would clarify this?

Not specifically, as I'm more interested in the production end, but I'm familiar with the claim, which is a quote from the director. I think VFX at the time is probably best understood like a guild system, and I can easily imagine how CG would seem invasive. Seems awfully topical right now.