This has been mentioned in posts before, but the way the above, whatever they may be

are implemented into CSBuild can be a little confusing. In my opinion, an 'illusion' wall is exactly that: an illusion. It is not a wall. You can see it as a wall, it looks like a wall but it does not impede your path ie can walk straight through it. A blocking wall? All walls block. But some can be moved due to their mechanics. DMute showed this well with a different graphic for an 'illusion', a wall that can be moved that is present, and a wall that can move back to a position, which is obviously not. Imagine the latter two as a door that can be opened and closed.
Any way, just my opinion, and would make designing, reviewing and reading files easier.