Angst Aversion: For people expecting a lighthearted Disney read, it might be a bit jarring with the heavy use of Love Hurts (between Scrooge and his love interest) and eventual dark turn the story takes which ultimately leads it to a Downer Ending. Thankfully, the final ending with the introduction of Donald and his nephews giving Scrooge an Adrenaline Makeover leaves things on a much happier note, much to the appreciation of many, by that point, choked-up readers.
In Voodoo Hoodoo, Scrooge looked like Donald Duck when Bombie the Zombie first went after him because that was his natural youthful appearance. Here, it was just a disguise, including the flattened sideburns, which are never visible in other pictures of him with Bombie.
Genius Bonus: The fact that Carl Barksalready had made Goldie wait for Scrooge in his old cabin for fifty years before he returned to him, something Don Rosa elaborated further in his narrative doesn't make this less of a Genius Bonus, considering that Henrik Ibsen had used the same plot device in Peer Gynt - Solveig waited for Peer in his old cabin just as long (whether Barks actually knew that much of Ibsen, is a moot point).
The last Beagle Boy to be ejected from Scrooge's dream met the Scrooge from the Klondike days and, after being defeated by him, threatened to sue Scrooge for "cruelty against bullies", since he couldn't brutalize anyone tougher than him. In "Attaaack!", Scrooge was complaining about being too old and feeble to handle criminals, prompting a Beagle Boy to claim he'd not like to meet Scrooge during his prime.
You know how Huey, Louie and Dewey are Not Allowed to Grow Up, but have remained their 10-year-old selves for what's hundreds of stories? Contrast with Scrooge who spends half a story being a 10-year-old, before visibly aging by the end of it.
"Holy Shit!" Quotient: Chapter 3 B: "The Cowboy Captain of the Cutty Sark". When you start to believe nothing can actually beat the Krakatoa's explosion, Don Rosa makes sure to prove you wrong.