The plain self-recursion part is not that great - especially one needs to write code in that TCO style. General TCO is a bit more - every tail call is a jump. I find it for example useful to have TCO code as low-level target for example for macros.

You have read a good selection of Scheme books. It's very useful to explore that style of programming and be able to really understand. Take it only as a hint, that there is more out there and that different styles and approaches exist. One can program with functions, one can program with linguistic abstractions, ... McCarthy called his paper: 'Recursive Functions of Symbolic Expressions and Their Computation by Machine' - this hints that one programs with recursive functions - but it enables also to compute with symbolic expressions - not only as data, but also as code. The evaluator as a recursive function, which implements Lisp.