Handling circular references is pretty important! Things like closing over an environment in a scripting language usually creates a cyclic reference, for exampl

Handling circular references is pretty important! Things like closing over an environment in a scripting language usually creates a cyclic reference, for example (stack frame contains a closure, which contains a reference to...the parent stack frame), or any graph-like data structures. There is also just a cost to maintaining reference counts, which may be expensive if you are cloning and dropping values very often. A garbage collector can mean that cloning or destroying a reference has zero cost instead, along with batching destructors like you mentioned. I'd also like to point out that technically reference counting is a garbage collection scheme! You can even use a cycle collector that runs occasionally over reference counted objects in order to free unreachable cycles; Python for example does this!