1. it's not a challenger.
2. she committed before she won wimbledon and obviously before she was top10.
3. money, and lots.
4. confidence. she's in a slump right now, and a string of wins could really help her mentally.
^^put those in any order you wish.
even if you think it's the money, what's wrong with that? she's a professional tennis player. playing tennis for money is what she does. this tournament would have no following if she wasn't in it. they paid big bucks to have a big name get the ball rolling, and i think it's worked beautifully.