I read that Barks thinks he became popular because of his riches which fascinate people. Maybe it is so, or maybe it is so because of the time period when he created Scrooge, or maybe it's not that at all. Who knows...
However, I was introduced to Scrooge by Carl Barks stories and I liked him because of his Scottish backgrounds (as I love Scotland), because of his from-rags-to-riches story base and because of the adventurous aspect of his personality. But I didn't love him, he didn't become popular to me personally until I was introduced to Don Rosa's version of his personality and family members' personalities, and to his more "mature" stories with tons of hilarious details.
In general to me it's his Scottish background and love for his roots, his family loving and adventure loving heart even though his greed for money and riches always shows more because he tries to hide his true heart whenever possible. It's also his temper, and I've never found the comics's style of over-killing, impossible feets of stregth as entertaining as any time the young Scrooge McDuck gets mad. And for the last but not the least, his love/hate relationship with Goldie and how they're made out to be the love of each other's lives, and Rosa even confirmed that she indeed will be waiting. I'd like to imagine him going to Goldie a little time before he dies of old age. It would be boring end in my eyes otherwise but not with the rich and colourful life he's had. To me it seems only right if he'd die after for a short time having the one thing he never went for in his life before; a wife/girlfriend. And especially the one he always held more precious than any gold or adventures. If there is a closure story for him and Goldie by Don Rosa, I haven't read it as such hasn't been published in my country.
To me his riches and money are just a sort of a plot device to everything I love about him. (: