He's a 6'5" goal machine.
He's only 23 and he's already the most dangerous player on the pitch when he plays.
Even though he hasn't hit the heights of last season, he still leads the league in goals scored and he's been injured for the last two months!!...and he's got over 3 months to go aswell.
Some of those misses against Chelsea were bad and costly but he was dealing with some sad news last week and that affects people.
But every good team had a prolific goalscorer; Messi, Ronaldo, Benzema, Lewandowski, Kane etc just to name some recent ones and guess what, they all missed chances too, so it's not going to be the last match it happens in.
You're right though, that he's not going to press like those players, but that's not his game, yet, but he scores more than they do and that's what we were missing before. (even though it never affected the team at the end of each season, we were always lamenting the chances we missed pretty much every game)
But he's playing under Pep, so he should keep learning and i'm confident his overall game will continue to get better and better.
Looking around, i'm not sure who you'd want to replace him with, but i wouldn't swap Erling for anyone!