I just looked for comments. From the archives, this makes the most sense to
me, from (rec.woodworking) October 1996.
"which keeps those small thins or narrow cut offs from jamming up
"when cutting thin strips that might fall through"
So I guess the answer to my question is "hype" when they say "zero
clearance throat plate increases accuracy and quality of cut". Except
maybe for smoothness of the bottom edge of the material but that depends on
how level the throat plate is relative to the rest of the base. I suppose
that smoothness might be more with table saws (like when cutting plywood).
If all that is correct, sorry, I should have looked in the archives first.
Think of it (and any additional comments) as a refresher :o)