I suppose I get the concept of closing a "loophole" of a law. Assuming the NFA is constitutional and lawful (which, IMO, it's not, by a long shot), it has always surprised me that a "pistol" could be allowed to have a brace of any sort yet escape being categorized as a shoulder-stabilized rifle.
Doesn't surprise me they're making this change. Also doesn't surprise me it has occurred post-election, though possibly that's coincidence.
Once a handful of the simpler RKBA stuff gets challenged successfully and erased by SCOTUS (as unconstitutional constraints), hopefully an enterprising group will have the "right" case come along that'll take aim squarely upon the NFA itself. Not likely, anytime soon, but it'd be nice.