Let's keep in mind that this is an end user application for pixel artwork. You and I might care that it's Rust. End Users will not. It could be written in Malbolge or BF for all an end user cares about.
Namespace collision is gonna be a pain for end users and newcomers, possibly depressing discovery, which is our point.
Plus first result for "rx rust" lead me to https://github.com/ReactiveX/RxRust