Is there such a thing as friends with benefits? I think that this is a good question. Speaking from the female perspective - yes, men and women can not only be friends, but they can have the benefits as well. In my experience, it is the men that have trouble with this concept.
I don't know whether it is the "friend" part or combining the "benefits" with the friendship, but the men I have met seem to be all about a "relationship" or having absolutely no strings attached. There is nothing wrong with either except that they want to say and think that they are after a friend with benefits.
From there we can break it into categories. First we have single men, never married, who are either too consumed with their work, themselves, or they are into the game/chase. Once they get the prize, they are no longer interested in any relationship at all. As I have heard man after man say, it doesn't matter how good you are, it is the game/chase that is the objective. They are just too busy or too whatever to take the time to be friends and realize the quality that comes with that relationship.
Then there are the divorced guys who are trying to find a companion and are a tad clingy, bitter, have thrown themselves into work to minimize the pain or anger from the divorce, etc. They are into the NSA because they are bitter or don't have time... or they are not into the FWB simply because they are trying to find a replacement for the companion that they lost.
And finally, we have the married guy who is probably more dishonest than the other two groups as he honestly thinks that he is looking for a friend with benefits as he has the commitment but is missing something. That said, the something that he is missing may be the chase or it may be the intimacy. One never knows what is going to happen with these guys. Most often, they do not know what they want and when/if they get it, they are not sure that it is what they wanted after all!
There we have it... I am seeking that friend with benefits. No commitment, no marriage, no nothing but pure and honest friendship. Dream the impossible dream!