Not OP, but I can guess.

D has a built-in GC by default and doesn't force you to manage memory like Rust. Also, the author mentioned that D is pretty straightforward to anyone with some basic programming knowledge (think C, C++, Java, and C# which fits the majority of coders). Rust is very different from those languages. My main goto language is Python and I can understand D a lot more than Rust which confuses me to no end (disclaimer: I'm a total noob).

Go is probably as easy to read as D if not more and is also GC and fast. It is also very spartan. I bet D has a lot of additional features.