Pin adds a huge amount of weird incidental complexity to your code base - since you need to pin-project your struct fields (but which ones?). You can’t just take an &self or &mut self in functions if your value is pinned, and pin is just generally confusing, hard to use and hard to reason about.
The article ended up with Vec<Box<T>> - but that’s a huge code smell in my book. It’s much less performant than Vec<T> because every object needs to be individually allocated & deallocated. So you have orders of magitude more calls to malloc & free, more memory fragmentation and way more cache misses while accessing your data. The impact this has on performance is insane.
Vec & indexes is a lovely middle ground. In my experience it’s often (remarkably) slightly more performant than using raw pointers. You don’t have to worry about vec reallocations (since the indexes don’t change). And it’s 100% safe rust. It feels weird at first - indexes are just pointers with more steps. But I find rust’s language affordances just work better if you write your code like that. Code is simple, safe, ergonomic and obvious.