No more odd than using Java. There's the huge difference in libraries and tooling but I don't think any inherent feature of Rust makes it less suitable for web backends than Java. I wouldn't pitch this project at work today but somebody has to go first.

Rust makes the most sense to me in a GraphQL/Falcor type backend. The lower number of endpoints combined with Rust's perf and focus on correctness seem like a better fit than templating out web pages.