Ok, ok ... no doubt about UX principles.
An article of uxdesign (https://uxdesign.cc/ux-trends-2017-46a63399e3d2) put it in a broader frame.
Here just an extract:
"The products and apps we design are used by millions - sometimes billions - of people, creating new markets, improving the economy, and shaping up how people interact with each other. While delightful animations and novelty technologies can put a smile on someone’s face, we have the tools and responsibility to impact much more than that with our work.
Why does one choose to use Gmail over Yahoo, Medium over Blogger - if the features are 99% the same? It’s definitely not about disrupting usability standards. It’s about that additional layer of sophistication that can only be achieved when you put enough time and brainpower into the tiniest details, the most subtle animations, the most elegant transitions – not just for the sake of creating whimsical dribbble shots."
By the way - I`m not advocating to use scroll speed in 'normal' webs or apps.
In a portfolio site or other creative projects it could provide a special kick.
It depends on concept, content and intended target group.
Well - principles are helpful, but please no orthodox discussion and usage.
You need always a good reason because more than ever the user will response by click.
Open minded ...