More flexibility. Almost infinitely more investment choices. You can pretty much do whatever you want, whenever you want with that Roth IRA.
Say your kid is a musical genius and has a chance to take lessons from some world renowned piano player when they're 12 years old, you can dig in to the Roth if you need to to make that happen.
Just keep an eye on the fees and investment expense of the IRA.
An interesting thing I just found while doing a little web research on this... Apparently, if you use Roth contributions to pay for a kids college expenses, they're considered income for the student. This affects their financial aid funds. Of course, if you're not counting on financial aid for your student, then this wouldn't matter.