At the park i go to with a bunch of tennis courts, there is a hitting wall. what are the benefits of using the wall? I've stopped myself plenty of times from going to practice on the wall when I didn't have a hitting partner because it felt like it was going to be a waste of time. I went the other day and felt like I was hitting pretty solid balls but when I played with a friend the next day my shots were all over the place. So I'm just wondering-- IS there a benefit to the wall? I'm sure there is, but I'm just not seeing it right now..