Not everything is reversible. Protected maps are readable by the game but may discard information about the development. For example the identifiers of variables, triggers, imports and such can be obfuscated, so you get a hard time making sense of them.
For simplication and community reasons, Blizzard created one format for both development and the game. The data of my map project is imported from external resources, which is why the game file itself is somewhat protected with each build and it does not matter when I lose/corrupt it.