Something to note about Scrooge McDuck and his thriftiness/miserliness is that as a character, he comes from a time where non-native born Americans(Read: Immigrants and foreign nationals) tended to be depicted in stereotypical fashion.

The common stereotype at the time for the Scottish was that they were all very cheap and thrifty to comical levels(Well, to be fair, most of the scots known to the English and to Americans were, for a variety of reasons, but it was exaggerated to absurd levels as all stereotypes are.)

Scrooge is kind of grandfathered into the Disney canon, but I can see why people might want to tone down character traits that could be seen as offensive to more acceptable and realistic levels, especially in a work where he's meant in a heroic role.

Although it should also be noted that Scrooge in the comics was initially a neutral and sometimes even a villainous character. It was only over time and with character development, changing writers, flashbacks to his past, and explanations of his more negative traits.

(And in what's considered the definitive canon in the comics, all of his worst actions happened during a period of time where he was angry, bitter, and depressed.)