The mods I do on the original entity files are small things such as increasing the resource asteroids around a planet and things of that nature.
I always make a copy of the original file I am working on, just in case it goes sour and I can overwrite it back to original state if needed.
Only way to learn is to dig in deep and gets your hands dirty 
I will try and overwrite the BIN .entity tonight with the .txt versions and test the game out when I get off work.
I will post back here if it works or not unless someone beats me to it.
*EDIT - This did work with 1.04 version while I was working on it. When I opened the .entity files in 1.04 they were in txt format and the game still worked fine. I have no clue though if it will work at 1.15.