DevilsPGD wrote:

A more interesting question, from a total layman, is this: If they
were willing to fly around in circles for hours, why not fly people to
their destination for hours instead?

They were sorting out a failure of the hydraulic systems which affected the
flight controls. They didn't want to venture too far from an airport, in
case they had to land in a hurry, but also didn't want to try landing until
they figured out what was wrong so they wouldn't upset things when they
added flaps and lowered the landing gear. In essence, they wanted to keep
things simple until they sorted out what was wrong.

Depending on the type of malfunction, I can see them not wanting to be
particularly far from a runway and perhaps this was that type of
situation, but at least from my point of view, if an aircraft isn't
airworthy enough to make a flight, it should be on the ground as soon
as is reasonably possible.

If they thought there was a major problem that couldn't wait, they would
have landed. As it was, they fixed some of the problems, and felt they
didn't need to land urgently, but by then couldn't make to their
destination, so it was easiest to burn off fuel and land where they
started.