It's a start... For clarification:
Static Entities should never change (should never need to be added or removed from the map, that's why they're static)
Destructible Entities differ from static entities only in that they have health and may be removed from the map at will.
These are now seperated from entities to differentiate between things that can accelerate (i.e. Moving Entities) and those that clearly shouldn't (e.g. a Cage or a JumpPlatform)
Hopefully that clears a little bit up.