You are taking into account the fact that u23 games are a similar standard as league 2. Niasse is championship level at best.
But yet managed to score 4 goals in the PL or against PL opposition.
First we had the 'he's a competition winner' and "he's never a professional footballer" shouts. Then when he scored goals in the U23's, it was the "just a bunch of kids", "poor opposition" shouts. Then he scored goals in the PL and still people are acting like he's the worst player to ever play the game.
Is he a top player? No, of course not. Is he graceful, definitely not. Will he score 20 goals a season? No chance. However, he does look like he has a knack for scoring goals, which at any level isnt easy.
We are paying him regardless, we may as well get some use out of him in the Carabo cup/if we qualify from the EL with a game to spare etc.