Will gach, cubes etc. soon become illegal?

Yes, that was my entire point. You can exchange real money for NX, and NX for real money. How is it not effectively the same thing? NX is an inferior store of value compared to cash because you have to use the intervening transaction to use it for things outside of game, but that doesn't mean it's not measurable in real money.

Real money that little kids are gambling away in horrifying quantities with absolutely no oversight or regulation whatsoever.