Impressive how..? It's just statistics-based very slightly fancier autocomplete...
And useful..? It's utterly useless for anything that requires the text it generates to be reliable and trustworthy... the most it can be somewhat reliably used for is as a somewhat more accurate autocomplete (yet with a higher chance for its mistakes to go unnoticed) and possibly, if trained on a custom dataset, as a non-quest-essential dialogue generator for NPCs in games... in any other use case it'll inevitably cause more harm than good... and in those two cases the added costs aren't remotely worth the slight benefits.
It's just a fancy extremely expensive toy with no real practical uses worth its cost.
The only people it's useful to are snake oil salesmen and similar scammers (and even then only in the short run, until model collapse makes it even more useless).
All it will have achieved in the end is an increase in enshittification, global warming, and distrust in any future real AI research.
It probably will, though, once model collapse sets in.
That's the irony, really... the more successful it is, the sooner it'll poison itself to death.