You can get the same effect with a block of code by properly naming variables and adding a single comment line if need be. It's really just a personal preference.
You'd have to have a standard vim config with folding to get it exactly the same.
Also, there's more restriction in that the single-use code block only has access to the variables passed into it, which makes it easier to parse, since less things could be happening. It serves to prune variables from the local scope.
