[Question] For what do we need Superintelligent AI?

Most of human problems could be solved by humans or slightly above human AIs. Which practically useful tasks – which we could define now – require very high level of superintelligence? I see two main such tasks:

1) Prevention of the creation of other potentially dangerous superintelligences.

2) Solving the task of indefinite life extension, which include solving aging and uploading.

I could imagine other tasks, like near-light-speed space travel, but they are neither urgent nor necessary.

For which other tasks do we need superintelligence?