Those that scout for a living tend to get very good with a stop watch. They also tend to play it safe and not anticipate. H to 1B times would be an example, most scouts are taught to start the watch as soon as they determine the bat is being swung. This usually puts it close to exact contact. Those that wait for contact sound or to see contact always have lower times, but they are less correct. Also it is easy to anticipate when stopping the watch. That is why so often scout times are slower than dads times.
We use technology for most things like (laser) these days. It's just more consistent.