So does it keep your from causing damage to your engine because it stops you from redlining?

 

Simple answer - float stops you from revving any higher, but is never used to define the redline.

If your engine is an "interference" engine (which means that the valves can hit the pistons if valve timing isn't right), you can damage internals from float so the redline is (or at least should be) governed or otherwise limited well below the revs at which VF occurs. In a non-interference motor, the redline is well below the point of float, but even if you miss a shift and reach VF you probably won't damage anything.