rails are not as easy to shoot as you might think (they do shoot small groups),but they require good bench manners and they also need to be properly set up and tuned just like any rifle, all the normal principles of bench shooting apply , and then some.
as for practicality , a rail is one of the best ways to test any component, be it bullets ,brass prep, powder, primers, actions and especially scopes , A rail can separate the good from the great and also the bad very quickly.
if you ever get the chance to sit behind one and shoot it make sure to give it a try you will probably like it for sure
hope that helps, good shooting