I was working for one of the major floor manufacturers when cheer switched over to spring floors in 2003-2004. I handled all of the cheer accounts, and when I was first approached by a major event producer I set my foot down and said, "No." My experience as a gymnast and a gymnastics coach told me that a spring floor was designed for one person at a time, not 30. We went through months of testing different placements of coil springs and foam blocks to be sure that we had a design that was safe and would withstand the demands of a cheer team. We had to make sure that when there was tumbling and stunts going on at the same time, that the tumbling wasn't double bouncing the stunts, causing them to be unsteady. We had to make sure that multiple tumblers, at different points in their passes (cross tumbling) wouldn't cause double bounces that would throw each other off. We set up entire floors and had people stunting, tumbling, jumping and dancing all at once on them. It took about 6 months to finally decide on a design that was appropriate for cheerleading....it was not just "let's put a gymnastics spring floor in a cheer competition". After all of that, we then had to figure out what would perform best on an elevated stage.
When you're talking about safety....yes, a spring floor is the safest performance surface out there. The 4" height of the foam blocks and/or coil springs creates a void between you and the subfloor. They also absorb a good amount of the impact of a landing. A carpet foam only floor (use in HS) will not do this. The spring floor will also help reduce overuse injuries in athletes, in addition to allowing them greater airtime to complete skills.