[jhgg]

These are optional features. You can decide whether or not you want to use them. No one is forcing you to do these checks at compile time.

My point is, the capability is useful to some people, and there are many other ways that doing arbitrary things at build/compile time can be useful or make things easier. The sqlx example is one of many.

Another usage, is calling out to another tool, e.g. a protobuf code generation tool. That requires the build toolchain interacting with another tool, that would "break the sandbox."

[jiggawatts]

The ability to reach .ru addresses is also convenient to some people.

Speeding down the highway as fast as possible is also convenient to some people.

Convenience becomes some else’s bad day.