I figured Wikipedia would be a fairly unbiased source, so I went there to try to understand who she is. She is a supermodel. Who speaks four languages, and spent a year in college - which means she had what it took to get to college - but above all, she has been modeling her entire life. She knows how to market, how to sell. That is what she knows how to do.
She has said that she wants to be a "traditional First Lady". Lord knows what that means. She wants to champion women and children. That could mean anything. And she wants to go after cyberbullies, like the one who called her a whore and had the potential to ruin her brand, so she sued, and accidentally claimed that it would hurt her when she was "the most photographed woman in the world" - I guess she thought people would like her as much as they liked Michelle - and then backtracked 'cause it made her sound too greedy.
So yes, having read that, I think she hoped to exploit being in the White House.
As for the letter, I retract any thought that she sold herself to Trump. I would say that they are a good match. But as for her actually doing something positive for the American people, I still don't think she has it in her.