Using a memory unsafe language in a situation where it's not strictly necessary is in my opinion not justifiable at all. It's the leading cause for security issues by some measures[1], incredibly hard to reason about and hard to debug. Honestly unless you have a really, really, good reason not to, use a managed language. If that isn't good enough and you want to be fancy use Rust and only if you've exhausted everything else start writing C.
The opposite it also true though: Using a memory safe language where it's not strictly necessary is not justifiable (e.g. Rust is essential for implementing a sandbox - for instance a WASM VM, but not for code running inside that sandbox - because the whole point of a sandbox is that it can run untrusted, unsafe code safely).
[1]https://www.zdnet.com/article/microsoft-70-percent-of-all-se...