Not only that, but Dex measures acumen with associated skills - thus, someone with high Dex is not only good at moving the way they want to, they know which way they want to move in order to keep a low profile. "Instincts of the cat", if you will.
Intelligence is also useful in hiding, but its primary role is to help you figure out better ways of doing so - it's not the instinctive ability to hide. Thus, the extra skill points a high Int grants are useful, just not as much as the initial Dex 'talent'. (Until you hit high levels, at which point a high Int will be far more important than a measley Dex score...)