Paging @JamesChristianson
As far as the usefulness of 7v7 as a recruiting tool, I would have to defer to the one who has played in the NFL and coached in some capacity at all levels (Charles Mincy). I would have to agree with him above and with his 11/21/2014 article on the home page "Charles Mincy: My Experience in Football, Part 2". Nothing compares to seeing a player play in a game.
Does the NFL combine really tell you how a player will ACTUALLY PLAY in an NFL game? Nope. Tom Brady's the best example of that. But, it is partly a way of seeing SOME skills...speed, strength and agility. They haven't done away with the combine yet.
Similarly, I could say that 7v7 is just another way to evaluate some aspects of a player's game and give some kid a chance with other "stars" when his team doesn't help him standout. For example, a good WR who has a horrible QB may stand out in 7v7 if his QB is, say, Jacob Eason.
I will say that the closest thing in 7v7 to an actual game is one-on-one battles with a CB and WR. And you can see whether a WR can break ankles, run crisp routes, read a D and feel where a QB is going...and you can see a DB's closing or recovery speed. In the Ford Sports Performance 7v7 team that I have been covering (as mentioned in another post), Salvon Ahmed is standing out like the freak athlete that he is, even with Gilchrist locking down the other side of the field.
If you think about it, players are evaluated mostly in training camps. Depth charts are created in spring and summer. So, that's not even 100% game situations, until you scrimmage and that's often not even real game speed and intensity, just like the regular season is not the playoffs. So, if players can be evaluated before the season starts, they can be partially evaluated in 7v7. And it's a chance to get high level competition without the full contact, as Charles mentioned. So, I don't think it has absolutely no value.
It's also worth mentioning (or may go without saying) that the coaching can dictate the quality/worth of the 7v7. If you just have kids playing loose "pick up" like games in practice and just running around getting open in games, that's not gonna give the scouts any good looks and the experience for the players is worthless. But, if they are actually training, working on footwork, reads, etc. with good game plans and working hard with intense precision, the work product is going to be close to game-like play, than with the sloppy 7v7 team/staff who are there just to kill time. You can't play full contact in pads year around. The kids gotta do something in the offseason. So, there's nothing totally futile about 7v7, if you're really putting in work.
I'm already seeing a difference in quality of work put in, among teams, this early in the 7v7 season. The programs/teams who put in real work are giving the scouts a little something to see, for sure.