You forgot the part where Those who own GW dont need this as GW has way more features this doesn't provide.
That's assuming those who own GW don't want to ever use any system except the one they already have. Maybe they want to change to a New or even *shudder* a 2DS. If this works on 9.x and keeps working beyond that, and if GW doesn't ever get to that point, I can see plenty of GW owners going for this, eventually.
Granted, there are a lot of ifs there, and we really don't know that much about this yet, just saying that owning a GW doesn't completely negate maybe wanting one of these, lack of features be damned.