http://www.fromholdjaffe.com/resources/articles/wills-trusts-estate-planning/why-should-i-consider-a-bank-as-a-trustee-of-my-trust/
Normal people don't know how to be a proper trustee. Even if you appoint a board of trustees (multiple people), most of them will slack off and jobs are done by one person and everyone else just rubber stamps.
Despite its fees, bank can be a good trustee. They are good at managing money, of course they are also good at collecting fees. :)