I don't remember which update exactly made it so I could no longer self-destruct debris or junk in creative mode, all I know is that it was a recent update, past 0.14.0. Sifting through patch notes didn't help me much to figure out the answer. Regardless, the question should be pretty self-explanatory. I liked being able to just select some debris which I didn't want to exist anymore for whatever reason, and just self-destructing it. Simply removing debris and having it instantly cleared, really doesn't look as nice in the middle of a battle or when cleaning up the aftermath of said battle, as having it blow up.
So, was there any specific gameplay or mechanics reason for why self-destruct was removed for debris in creative mode? I honestly can't think of any, because it's creative mode, so the whole point is being able to freely do whatever you want, whenever you want. For me, at least, it's done nothing but slightly hinder the fun I've had with being able to select anything I want and being able to blow it up. This isn't game breaking, obviously, it's just somewhat annoying, and I'd appreciate some explanations just to clear it up.