Why would anyone want to rewrite anything in C++ given they can choose anything else? Like Rust or Go or C or Zig or literally anything else.
I wouldn't choose Go because GC is a non-starter.
I wouldn't choose C because it's nice to have some form of generics or metaprogramming, even if templates are not exactly fantastic.
I wouldn't choose Zig because the language isn't stable, and the lead developer has hinted that they'll drop LLVM down the line, and I don't want to beta test their compiler backend.