Wordpress also highlights the tradeoffs anything that abstracts over the underlying code...doing something specific means both knowing significant technical details of WordPress and some non-trivial amount of CSS, HTML, Javascript, and PhP and the specific implementation details of the site in question. If the site is leveraging a significant portion of WordPress's capability then the overhead that comes with using WordPress may be a valuable tradeoff. Likewise if the person maintaining the site has a business doing WordPress sites then they can bring WordPress expertise to bear.
But for a general professional programming practitioner, the more universal tools of programming languages are applicable in more situations...knowing HTML and CSS is useful when working with WordPress and the more expertise a person has with the general tools, the less advantage there is to using WordPress.
Going down the stack from WordPress is possible. But it's still pretty much the case that if I'm using a GUI editor on the happy path, I don't care that it's using React. Using or not using React only matters when I'm off the happy path and have to figure out what the GUI did.
The last problem with front-end development in particular is that committing to a tool is risky, in two years there's a reasonable chance that the underlying technology of the tool will be out of the mainstream: e.g. Angular (one) today.
Good luck.