OK, but you also get no stack traces when you use a loop. I am not really seeing how this is an argument against TCO, it sounds more like an argument against anything other than unoptimized recursion.
And that's one reason why loops are hard to debug!
Losing stack frames for recursive functions is not so bad. The real violence that TCO does is to non-recursive tail calls, which form the majority of tail calls, at least in non-functional languages.
