In practice, though, writing stuff with `Arc` or `.clone()` or `Any` is not as easy as it would be in Python because you've got to write a bunch of extra boilerplate. It's much easier to have local `i64` values that you can pass around as `Copy`. So if all you need are local i64s, then you'll take the easier option and do that.

The same is true at multiple levels. `.clone()` is relatively easy to use, although once you learn the basic rules for referencing, that also becomes easier. `Arc` solves a specific problem you run into at a certain point sharing data between threads, but if you're not sharing data between threads (and most of the time you're not), it's just boilerplate and confusing, so you might avoid it and at worst use `Rc`. `Any` is rarely an obvious choice for most contexts, you really are going to only use it when you need it.

The result is that for most simple cases, the precise and "proven" option is typically the easiest to go for. When you deal with more complicated things, the more complicated tools are available to you. That seems exactly what the previous poster described, where you can decide yourself how much you need to prove a given thing.