Removing Shadow DOM boundaries from text editor elements

So, does this mean the shadow DOM is a bad idea, in general, or is there something special about Atom that makes it a bad idea for Atom or maybe even text editors in general? If so, what's the criterion to use to decide whether one should use the shadow DOM?

I still feel like using web technologies to build an editor was a strange choice. (Though I don't mean to disagree with the reasoning here, which sounds OK to me.)

I wonder if there will be any performance benefits from removing Shadow DOM in Atom.

So Atom just discovered BEM? To be fair, I only just started getting into it too; it is incredibly useful for organizing CSS.