[jasonkillian]

I don't disagree with you on readability being important or on the value of developer time. It's just that the marginal costs of `memo`, `useMemo`, and `useCallback` are quite low. They don't add cyclomatic complexity, they don't increase coupling, they can be added to code essentially mechanically and don't carry a large cognitive overhead to figure out how to use, etc.

The main downsides are that they take slightly longer to type and slightly decrease the succinctness of the code. And then there are a few React-specific complexities they add (maintaining the deps arrays and being sure not to use them conditionally) but these should be checked by lint rules to relieve developer cognitive load.

Of course I'd rather not have these downsides, but in the end, it's still much less developer overhead than having to constantly profile a large application to try and figure out the trouble spots and correctly test and fix them post-hoc. And it means users are much more likely to get an application that feels snappier, doesn't drain as much battery, and just provides a more pleasant experience overall, which is worth it imo.