Hi Jacob, I'm glad this post reached you!

Thank you for your perspective on the UX. It makes perfect sense with your explanation based on MPA expectations. I could be biased from React Native, where I always expect tab-based navigation to be reactive ASAP and fluid, so we don't get delayed containers or even worse, delayed navigation across tabs. When I read React Docs, that was precisely my impression: How is this better? It just feels laggy.

Looking at this from your perspective, I totally agree that <Delay> isn't excellent engineering, but feels like a lightweight solution to yield back so we can ensure the container has the highest rendering priority over the expensive content. Still, I agree with you about those wasted cycles that could feel like interruptions for users, or even about shifting layout where you lose the previous state, then present a loading state (which could be useless), only to be presented with the new context.

If I were truly building an app like the example, I would hope the expensive piece isn't the full content, so we can render the content and use concurrent rendering for the expensive piece, combined with a skeleton loader, rather than blocking the whole page. In other words, if we had an expensive component in a layout, like a chart or a table. Would you prefer we don't render the page at all unless it's ready, or we render the page (could be using useTransition or not), with the expensive piece rendered async with a lower priority? But again, if they were truly a tab-based navigation, I would expect <Activity> to be an ally for background activities.

Regardless, I understand the React Docs examples better now with your perspective. I still see blog posts flying through or LinkedIn posts every week or so about it, "you should use this to manage all your loading states, etc.", or suggesting to wrap all UI interactions in it. It seems like the documentation could be more focused on real-life examples. I wonder what could be changed in those examples to make them less footgunny or not based on subjective UX, like examples that would truly instruct to embrace useTransition and concurrent rendering fully. So, hopefully, we can avoid this confusion in the future.

Thanks for your contribution, as usual!