Personally, I’m weary of software written in languages without memory safety that are more likely to have long living exploits only known to certain government authorities.
Also, I'm less concerned about the memory safety than the _complete reimplementation of SSH_ from scratch. So give me OpenSSH any day for things that are actually important.
The feature turns off extra compile time checks. That’s it. It doesn’t mean the program is correct.
This program still allows potentially damaging things like `rm -rf /`. So, it’s not data safe. It’s unknown whether it’s secure safe either, since it’s not been audited and it’s still “alpha”.