If you are in any way close to neutral, there is no need to purge all the ballast. Just a little makes you positive.
In the type of diving it is designed for (single tank, no BC, no dry suit), there is no sudden loss of buoyancy that need a sudden loss of weight.
The main risk is actually a sudden loss of weight or the ability to add weight if the water valve or pump fails. and corking to the surface.
In normal operation buoyancy due to breathing down tanks or wet suit decompression occurs slow enough for the pump, and there are no sudden buoyancy adds other than accidentally dropped weights.
I actually like its design, it just isn't useful for the type of diving I do (dry suit, side mount, etc.). For warm water single tank diving, it sounds great.