Animation, physics systems, AI, load times, amount on screen...will all benefit from extra RAM.
"Graphics" will not.
Depends what you define as "graphics", if you mean higher resolution textures, higher screen resolution, more geometry (polygons per character etc)...then NO, extra RAM does not help there.
The PS4 will be topped out at a maximum of 2GB of the 8GB used for graphics. That is to say that no more than 2GB will be used for video/graphics duties.
It is based on same GPU as AMD 7850 which does not have a 3GB variant for a reason, because it isn't a card suited to situations where the extra RAM would be of any practical purpose.
This all pertains to graphics, of course the extra RAM will benefit areas that some may deem as "graphics", as in to say open world type games, but the textures and so forth used won't be any better because of the RAM, it just means those games will be able to be created.
Also, I posted numerous times in that thread explaining this so I'm offended you'd ask the question again. Most people on VGChartz don't have a clue about this stuff.
If you don't believe me (I don't exactly have a track record for technical knowledge on this forum), then just ask someone like Soleron to post what they think and I can promise you they will simply affirm what I'm saying, although possibly with a better explanation.