I mean, yeah, you can avoid wrapping things that are optional in Option, but that doesn't make that the result is semantically meaningful. If you have a User struct with "age: 0" does that mean:

1. The user being referred to is a newborn, or:

2. Some other code, locally or on a server you're reading a response from, broke something and forgot to set the age field.

It's not just Rust that gets this (in my opinion) right, Kotlin and Swift also do this well at both a language and serialization library (kotlinx-serialization and Codable) level, but this quote from this article comparing Go and Rust is generally how I think about it:

> If you’re looking to reduce the whole discourse to “X vs Y”, let it be “serde vs crossing your fingers and hoping user input is well-formed”. It is one of the better reductions of the problem: it really is “specifying behavior that should be allowed (and rejecting everything else)” vs “manually checking that everything is fine in a thousand tiny steps”, which inevitably results in missed combinations because the human brain is not designed to hold graphs that big.

https://fasterthanli.me/articles/i-want-off-mr-golangs-wild-...

Basically, if you do not want it to be wrapped in Option then you should either:

1. explicitly specify a default—which can, but doesn't have to be 0.

2. fail immediately (as this article explains) when trying to parse some data that does not have that field set.

and if you do want an Option, you just need to be explicit about that.