It's very useful. I once had a codebase where we wrote two (parallel) variants of trampoline called tramampoline and trambopoline, and I'm not even a little bit sorry.

I'm looking at the source, but I'm not sure why "without stack consumption" is true. Is this because trampoline is written such that it takes advantage of tail call optimization even if the inner function doesn't?

https://github.com/clojure/clojure/blob/clojure-1.9.0/src/cl...

Yeah trampoline is kind of rare.

You only see it in cases where some functions are mutually recursive.