I think that since a significant portion of Rust developers come from a C++ background, and C++ uses basically the same set of symbols, it's not a huge barrier to adoption
There's really only one sigil in there that isn't in C++ (the ' single-quote to name lifetimes and labels). And it's missing several ambiguities that plague older C++ grammars (i.e. is >> a greater than, or closing two template expressions?)
