Do Indie Games need approval to be commercialized?

No, your game does not need to be judged or verified by the Epic Staff.
And just to clarify, you don’t have to pay 5% on ALL your earnings: (From the EULA) Licensees are not required to pay royalties on the first $3,000 in gross revenue per Product per quarter.
If Product revenue is less than $3,000 in a quarter, licensee is not required to report revenue for that Product.
Financial winnings from awards are exempt from royalties.