Because i've proven that that method is no more effective than the one the extension uses, and I'm not rewriting an entire program on the whim of a paranoid fool.
Ahh!
Personally, I wanted to use it to 'bulk up' my SDB. I'd love to brag that I have 100K+ items sitting around in my SDB. I tried by hand to get this using essentially the same method as written in the program, searching for items (Specifically, mallard balloons) and looking for 1NP (to 10 or 20 NP) shops and buying everything.
I gave up at 2K. xD Took me almost a day and to be honest, was incredibly boring.
That's why I personally want it, not because I'm paranoid.
As for rewriting the whole thing, I would imagine all you would have to do is switch the quick stock option to 'deposit' as opposed to discard.
In any case, just my two cents. I obviously don't know how long it would take to make such a change as I'm not involved with any programming outside of Turing.