I'd buy them. After a you have all the top equipment , there really isn't much to spend credits on except golf balls. Other than that, you just gamble them away with tourneys and challenge matches etc.
There are avatars to buy, but I have more than enough of those. It would be cool to buy different hats and maybe even shoes. But I'm sure WGT would try to make too much money on a few sales vs making them fairly cheap and then more people buying multiples to have different colors.