Garbage Collection.

The content of the stack is (always?) known at compile time; it can also be thrown away wholesale when the function is done, making allocations on the stack relatively cheaper. These FOSDEM talks by Bryan Boreham & Sümer Cip talk about it a bit:

- Optimising performance through reducing memory allocations (2018), https://archive.fosdem.org/2018/schedule/event/faster/

- Writing GC-Friendly [Go] code (2025), https://archive.fosdem.org/2025/schedule/event/fosdem-2025-5...

Speaking of GC, Go 1.26 will default to a newer one viz. Green Tea: https://go.dev/blog/greenteagc