Money (alone) can't buy you happiness!
Carl Barks' genius is not only about his wonderful art. Carl Barks was an excellent storyteller who used his stories to not only tell jokes and send these characters on great adventures. He also told us about how they were as people and...
...used them to examine real issues. Uncle Scrooge started out as a penniless prospector in the late 19th century, and by utilizing his smarts and work ethic he built a vast mining/shipping/media/oil/just-about-everything-else empire that resulted in his three cubic acres of swimmable cash money. He's the classic American character (even though he’s Scottish) who embodies the Great American Dream. But it's not easy and Scrooge does not live life on easy street.
His vast wealth is a constant source of stress, so much so that one story ('Tralla La') involves him moving, because his nerves are shot, to a mythical land deep in the a Himalayan mountains where the people have no money...
That story then becomes about what happens when the concept of wealth is introduced to a society that did not have it previously (Hint: it's quickly destructive). It's thought provoking stuff that, had it not starred walking and talking ducks, might otherwise be found on a socially conscious program like decades later in The Gods Must Be Crazy.
But this is no anti-capitalist screed. Uncle Scrooge is presented, for the most part, as someone to be admired for his hard work and cunning.
Barks just makes it clear that money can't by you happiness and peace of mind.