I'm not sure what you were told, but I'm guessing what they're looking for is athleticism. A high school or college pitcher who can hit is probably more of a natural athlete than a pitcher who can't (note that in high school and sometimes even in college, the same player is probably pitching one day a week and playing a position when he's not pitching). And I can imagine a scout generally preferring an athletic pitcher to a non-athletic pitcher.
But to the idea that an organization would scout a high school pitcher to evaluate his future ability to hit in MLB, again, I've never heard anything like that and find it highly unlikely. I suspect if you asked Keith Law or one of the Baseball America guys in one of their online chats, they would confirm my suspicion.
Pitching in MLB is really hard. Hitting in MLB is really hard. I think people don't realize how difficult it is to do both things well. For example, Tim Hudson was an absolute hitting beast in college. His senior year at Auburn he hit .396 with 18 HRs. Today, as far as pitchers go in MLB, he is considered a pretty good hitter. Which means he has 2 HRs and a career .166 BA. That's how hard it is to hit in MLB.
To me, one of the most amazing stats in MLB is that Tim Lincecum has 37 career hits. The fact that he has any is pretty crazy. Dude didn't bat after his freshman year of high school.