If you make, for example, dust, then change its ctype through the console and make it fall on a clone, it will only create the "pure" material, with no ctype. This forbids, for example, to make molten phot* (!?! Photons shouldn't melt) in infinite quantites.
@arcadiagiulio There is practically no use for this, and nowhere to save this second ctype. The CLNE just clones the element you shove next to it/drag over it. That sets its ctype. Are you going to code it yourself? No? Exactly.
Well, I know it's hard to implement, but now it may become useful with the CONV material - in fact, I was going to make something like a breathing machine, and I had to use something to change the air.