I agree with your point.

But I usually prefer the later anyway, because the code usually is not as nested anyway and having a name is often helpful, and also because I find the nested code with lambdas also not too readable. Other languages have better syntax for chaining functions in this way, i.e. with lambdas I would like to write like this:

  foo(arg1, arg2, _)
     .(int(int x)) { ... }
     .(int(int y)) { ... };

(edit: or something, I think I got it a bit wrong, but you get the idea)

But I agree, sometimes lambdas are better so it would be good to have both.

(There is the classical hack to define lambdas using statement expressions and nested functions.)