That is the value of soft toss. Easy to see swing flaws, as well. We always have our kids to take a round of soft toss into the sock net before they hit live in the cage. Gets them loose, concentrating, and ready to hit live. In the cage, coaches always throw BP in our practices, and that has been the case with every team that I have ever coached.
We sometimes have kids throw "live" on the field in a scrimmage type situation. It allows the kids to see kids throwing live, (more their own height which definitely affects the path of the ball to the plate as opposed to the path of a taller adult) and also allows the pitchers to throw to a hitter. I've seen so many kids that could hit the coach with no problem, then step in against a kid, the "fear" sets in, and they can't hit anything. With those kids, get out of the way is first on their minds. Hitting is definitely second. As a coach, you can't fix that fear. When the kids start "chucking" it, you find out who your baseball players are. Pitching live, also gives the pitchers a chance to work to a hitter. Some kids can throw nothing but strikes in the bullpen, but put a hitter in, and they can't find the plate with a search warrant.
A lot of the trend in baseball practice is to have stations with individual instruction on various things for the first part of practice, then try to put it all together at the end of practice with live infield/outfield, and baserunning at the end. It usually works out very well, but it definitely takes a plan, and assistant coaches that know what they are doing. If you don't have good assistants, it won't work. In the hitting side of practice, we usually would usually try to split the kids into 3-4 stations, with tee work, soft toss, live in the cage and then mixing something in like the "drop drill" or "toss from behind," two ball soft toss, asking them to hit the top or bottom ball, (you can do this one with different colored wiffle balls) or the hitting stick which I have never been a fan of and usually discourage.
As far as pitching, we usually would try to mix in pitching only practices if we had a portable mound or access to the bullpen mounds at our facility. I always would ask for my pitchers to run after practice, because I feel that legs are so important in keeping the arm sound and strong.
The worst practices are the ones where everyone spreads out to shag balls while one kid hits and nothing much is getting done. I haven't seen one of those in a long time. I served as "Coaching Development Director" for a few years at our Little League before we left this year for travel baseball. I always had a spring and fall coaches clinic where we would give the coaches ideas on practice planning and instruction. I usually would invite a couple of the High School coaches in or have some of our veteran coaches to help out with this. It worked wonders for our League and raised the bar for the coaches. Bad coaching was not tolerated and coaches were reviewed by the parents and league officials every season. Bad marks and you don't get to coach the next season.