It could certainly help them narrow the field, though. Obviously they're not going to sign a girl they've never seen play in person. But if they've gotten emails from 200 different girls, they're not going to go see them all either (I made up that number - I have no idea how many they actually get). If they could narrow it down by watching a couple of innings online, it could save them time. It doesn't seem to have much of a downside, at least.
To your point of narrowing the field, for both coach and player the recruiting process is one of elimination not selection. Contrary to popular belief this is not like falling in love where things just happen and you get an offer. Coaches have a list, often lengthy, of kids to look at and one by one they either cross them off the list or keep them for further consideration. As a coach you want to narrow the list to the best of the best. As a player you want to be on the list as long as possible.