Not entirely what I was saying, it's one of the patterns I've seen and those that use arrays and indexes into arrays as "handles" will also vehemently disagree with me when I say they just implemented "we have pointers at home".

Those are pointers, there's slightly more protections with them but depending on how you model it use after free bugs are back on the table when doing that. At least buffer overflows shouldn't be possible since that is runtime checked.

It’s possible use after free isn’t actually possible because Rust’s ownership system lets you express lifetimes that the compiler enforces (or you enforce it at runtime yourself).

But handles aren’t uncommon even in c/c++ - it’s nothing to do with the language and more how the author thinks the particular problem domain is best modeled.