[gohrt]

Submitter's editorialized title mischaracterizes the OP

> All the tasks focused on iteration on a collection using a C++ vector object.

That's comparing "functional style" collections to iteration.

It is readily apparent that C++ syntax is so troublesome that "functional collections" won't be a win for small iteration blocks.

We had the same debate for functional Java collection methods (although the Java 8 lambdas tilt it more closely in functional Java's favor)

The main use case for C++ lambdas is for declaring callbacks.