The difference is that named generations don't claim that any differences are due to supernatural influence. Instead they are arguing that the differing circumstances in which people grow up and live influences their experiences and how they see the world. That is a MUCH more defensible position.
It would be defensible if it worked that way. Instead they work backwards: define the groups for marketing purposes, and then try to identify the similarities.
That's irrelevant to what I wrote. Whether it was made up by marketers or anyone else doesn't change the fact that unlike astrology it doesn't make an appeal to magic.
The name of the generation gives you birth years. It also tells you "hey the generation 2010-2020 are getting hit by AI a lot more than the previous ones.
This not astrology at all. Astrology is 'magic thinking'.