I wouldn't say mariginal. I'm all for disbanding race centric groups, I think they are ineffective. The only way to get people to treat each other as humans is exposure to one another which doesn't happened when we form social groups based on self-segregation. That being said the idea that whiteness has "marginal" cache seems like a great understatement to me. Just from my experiences in the south and north, with people who did and did not know I was partially African American. There seems to be a lot of stereotypical ideas still in some people towards black people. From all races, even blacks themselves. It's a level of mistrust and underestimation of abilities that I don't see directed towards other groups. I've had people say "I know it's wrong but I still get scared around a group of black guys". Black groups are more likely to be seen as delinquent whereas no one is nervous around Frat bros despite thy demographics history of drug use, rape and violent hazing.
And of course there studies like in freakanomics where "Jason" gets a job over "Rashad". I think "marginal" is very much an underestimation where whiteness is concerned.