Welcome to Rails 7!
I’ve been with Rails since Rails 1. It seems every major release of Rails there are major paradigm shifts. Best practices change. Rails drives a number of these changes, and keeps up with others.
How Rails interacts with both JS and CSS is the biggest change with 7.0, and Tailwind’s integration is a bit further ahead that Rails’ integration with other CSS frameworks in two important ways: there is no node.js dependency, and the scaffold templates generated are enhanced.
As a book author, tailwind has allowed me to replace pages of text with lines of css atttributes. And hotwire allowed me to remove an entire chapter. The end result: a book that focuses more on Rails and less on web technologies.
Rest assured, if tailwind is not for you you are welcome to use a different CSS framework. Or no framework at all.