Why did Hermione erase her parents memories?

Has anyone ever wondered why Hermione erased her parents memories instead of just using the Fidelius Charm to protect the house? You make Harry the secret keeper because if Voldemort ever captured Harry, he would never need Hermione's parents as leverage against Hermione.

I also don't think the charm is too difficult because as Hagrid said, "An' they haven't invented a spell our Hermione can' do"