The way I read the proposal is that they used a real-world example from a commonly used codebase (React) to demonstrate how this feature would improve it. I think that's a good approach as features are intended to address real-world concerns, and concrete real-world examples help with that.
I don't think it's fair to say it's "cherry picking" to focus on the example they focus on themselves. They have a few other examples too, but I would say "I don't see how [NEW] is better than [OLD]" for many of those as well (and for some, I think the [NEW] is significantly worse).
Considering it was their opening example (which they reiterated multiple times) I will concede it was a poor choice. Since yes one of the top goals is selling the general idea. So it's fair the general audience would take it at face value, especially when they use it multiple times as a real world use case, it is hard to take it any other way.
Plus the doc is #1 on HN after all, which could IRL push it beyond a proposal stage if done right.
I don't think it's fair to say it's "cherry picking" to focus on the example they focus on themselves. They have a few other examples too, but I would say "I don't see how [NEW] is better than [OLD]" for many of those as well (and for some, I think the [NEW] is significantly worse).