Yes, when your project is just a single functional layer -- e.g react -- you can then subdivide your code along feature lines. But the entire codebase will include server side code, DB code, and lots of other code that cuts across functional areas and for which you are going to have a hard time organizing it according to features.

Do you put bits of the DB schema definition files/SQL code in there as well? Back end server code? What if it's a completely different team working on that code? What happens when you decide you want a permissions engine or data access layer and need to couple your UI logic to those layers? When you add a replication engine to synch state across different instances, or a dedicated code handling session management, etc.

Over time, the code is going to reflect team structure and functional roles rather than features, and you can really organize by features only when there is one functional area -- e.g. a react app.