In your case it might be less useful, though you are making a lot of extra actions (?). Sure, you might achieve the same doing it your way, but people tend to reduce the number of (redundant) steps.
Two big pro's for prldr for me are:
(1) As titles of posts do not always explain the content in a good way I do not know if I will read it, using preloaded rss (prldr) I can quickly open all items consecutively without moving my mouse, just pressing "j".
(2) When I find something interesting, or at least think it is, I can scroll in my item and still use "j" or "k" to jump to the next item when I decide the article is not what I expected / want at the moment.
Summarizing, prldr might not be the thing for you as it is now, but I think a lot of people are not using their (google) RSS Reader(s) in such an advanced way as you are.
