SavingforCollege.com reports 2015 average for all 529 plans was 3.09%
Forbes July 18, 2013 issue reported: "Over the past decade the inflation rate for public four-year colleges was 5.2% [annually]". The implication being that 529 program earnings are not keeping up with escalating college costs. Savingforcollege.com reports: "As the custodial parent of a dependent student, your non-retirement investment assets are assessed in determining your child's Expected Family Contribution (EFC). Any 529 accounts under your ownership are counted as parent assets for this purpose.”
The US federal Tax Code allows withdrawal of all amounts paid into a 529 Educational Savings Program (your equity) at any time for any purpose. You are allowed to adjust to zero the amount of your monthly contribution to a 529 Educational Savings Program. Having any savings in a 529 Education Savings account negatively impacts eligibility for need based financial assistance and may have negative impact on some merit based scholarship offerings. By law Roth IRA account value is excluded for assets on the FAFSA application. 529 Educational Savings Accounts are subject to penalty and income tax if they are not used for the specified individual for qualified educational expenses.
A logical interpretation is; a 529 account might not accomplish your objective and could become a tax problem if your child elects a non-college option. It could be a hindrance to receiving financial aid.