Emulation seems fine for Rust. I don't think there's a good answer to this anecdote. One option is that when I learned C++ I built an emulator to learn how to write an emulator, whereas people writing emulators in Rust are perhaps often trying to learn Rust. Maybe that leads to a difference.

It's basically impossible to say though, we'd need to do a full survey of the C++ and Rust emulator ecosystem and look at which bugs are most prevalent, control for authors experience and skill, etc...

edit: I'll also note that when I built an emulator there were guides for it in C++. I don't know what materials exist in Rust but building an emulator is actually a project that I would consider C++ for (if for learning purposes) just because it's so well documented how to build one using the language.