It is better but probably Celtic as a team aren't significantly worse than any promoted side.
The bloke moved to Celtic at 19. He is now 22, 59 games and 37 goals in the last 2 seasons. 3 in 3 this season or 84 games 49 in total. However you put it it's impressive. Bad league maybe but the blokes going to be 100m+ in 2 seasons time when he gets his break. He doesn't need a loan to a top league to prove his worth.
Better to go your own way than stay stagnant on PSG's bench.