"there's no need to use switch statements and their associated complexity to map integers back into addresses, when all that's really required is for the "caller" to supply a where-to-go-next address."
There's nothing quite like implementing an abstraction, then turning right around and unimplementing the abstraction as a layer on top. (See also: using relational DBs as key/value stores. Bonus points if it implements a hierarchy that looks like a file system! Implementing unreliable data delivery on top of TCP (which can be done by reconnections). Taking a character/block device and implementing block/character access. Implementing streaming on top of page-based abstractions like HTTP, implemented on top of streaming via TCP; there's "official" ways to do this but for a long time it qualified.) If you're wondering where the CPU cycles are going....
I don't understand what abstraction is being unimplemented with a layer on top here. Whether you use a stack or avoid it with [multiple] link registers, those are both reasonable methods of getting back and neither one builds on top of the other or undoes any work that's already been done. Whether to use tokens or addresses has tradeoffs, but I still don't see any work being unimplemented.
At worst they avoided a stack and made an implementation that was unoptimized in an entirely unrelated manner, not because it unimplemented anything on top.
There's nothing quite like implementing an abstraction, then turning right around and unimplementing the abstraction as a layer on top. (See also: using relational DBs as key/value stores. Bonus points if it implements a hierarchy that looks like a file system! Implementing unreliable data delivery on top of TCP (which can be done by reconnections). Taking a character/block device and implementing block/character access. Implementing streaming on top of page-based abstractions like HTTP, implemented on top of streaming via TCP; there's "official" ways to do this but for a long time it qualified.) If you're wondering where the CPU cycles are going....