Actually the terminology/scale is really similar to what many NFL teams use (or at least used a few years ago). You can quickly categorize with the letters, so if you're a franchise that, say, doesn't like small players, you can filter them out easily. Less handy when you know the 300 draftable prospects, but vital when you're sending scouts to every no-name school in the country.
FWIW, Lande called Richard Sherman a 2nd round pick pre-draft (one of the reasons I liked Sherman, even though I was rather hesitant about big corners in general). He has a handful of grades that are out there, and a handful of them end up looking brilliant while some just look stupid. I always buy GM Jr though, not because he's always right, but I am reasonably confident that his grades are based off actually grinding film.
Sarlacc, on comparing .NET to Soccer: And why not? It's a bunch of people running around in circles, feigning pain, and never scoring.