I actually disagree here pretty heavily and think that this doc is due to the bar for competent developers going down in recent years (due to the rise in necessity for more developers of course). There's almost an expectation that powerful tooling should be dumbed down.

The entire doc is written around two common problems:

* You don’t need Effects to transform data for rendering * You don’t need Effects to handle user events

Both of these problems do not occur if you take the time to understand the tooling React gives you. The events point should be a given, that's just React 101 (and yet they have to spell it out to people...).

You don't end up using useEffect to transform props/state and generate new state if you understand that those things are just variables and you can instantiate new variables using them inside the scope of the component function.

"But that's inefficient because of how re-rendering works".

Great, you understand how re-rendering works but haven't gotten familiar with the useMemo hook. Come back when you've gotten familiar with the primitives available to you in React and how they can all work together in different ways, there's not that many of them!

This doc reads to me like a DIY store publishing an article about how you shouldn't hammer in screws even if it kinda seems like you could if you didn't take the time to understand hammers, screws, and nails. It's sad that it needs to exist but that's the current state of engineering.