Your question is a little odd, Torrenting “manually” and torrenting with the -arrs is the same in “process” and you will use the same amount of diskspace (not accounting for the programs themselves that is).
Using the -arrs is what make the who torrenting process a little more “automated” as you specify the content you are looking for, and once that content it available the software pulls it from whatever sites or index’s you have provided in your initial setup of the programs.
No more having to look at multiple sites for something, as soon as it’s online the arrr pull it and download it as soon as possible for you.