LL: yes, I have read something about Pauling.
The difference between natural vit C and synthetic vit C is still quite big. Synthetic C contains only ascorbic acid, while natural vit C contains the following: rutin, vit P, factor J, P, K, tyrosinase, ascorbigen, ascorbic acid.
Natural vit C is expensive, however, you have to get it from fruit or something. Like you said, ascorbic acid is still produced by animals in their livers, so I assume that it is useful on its own (haven't even claimed that it would be useless), I'm just no fan of megadosing things at least over a longer time, doesn't probably work for everyone either, some people can get kidney stones (I've heard), and flooding your body with ascorbic acid the whole time can be a bit rough on the kidneys anyway. And it was efficient for me too, but I belong to those people who don't like excess amounts of it.

Another example is vit E, the synthetic form contains only dla-tocopherol (a less potent version of the natural a-tocopherol), while natural vit E has a,b,c,d-tocopherol. Natural forms of vit E also contain four different tocotrienols. Fortunately getting real E is easy and not expensive even.