Beckford was PL standard in that he played and scored in the PL. Ditto Niasse.
They may not be the top PL standard but the fact they played and scored is enough.
And Calvert-Lewin has scored 1 in 14, but he is PL standard ?
So you're saying anyone who has played and scored in Premier League is up to standard? Beckford was never PL standard, we took a punt on a player for free because we were skint and he was about all we could get and got rid of him after a year. There will be hundreds of average players who have made fleeting appearances in the PL over the years and managed to scramble the ball over the line, it doesn't mean they were ever good enough to play at the level.
Niasse was struggling to get a game ahead of Mbokani at times, his record at Hull wasn't anything special. It probably says more about where we are with striking options that people are even trying to suggest he did well there.