I'm aware this absolutely not the same thing but in league of legends eSports, at international tournaments the teams in the tournament often practise against each other in the lead up to and during the tournament.
Pretty notoriously, the teams that do the best in these practise matches essentially never win. Grand final matchups where one team has 100% record against the other in "scrims" only to get completely demolished in the final.
My point is, practise is wasted if you don't lose it to try things that might result in losing.
Yeah he tends to go on nice little runs when we have an injury up front too. He could be more clinical, and he absolutely has times where he offers not much, but he's shown he can step up as a backup. For a position where we don't even have a clear number 1, we sure can't ask for a world class number 3.
In saying that, if his sale will help fund a pickup like gyokeres, guirassy, or oh my days osimhen, while they're unproven in the prem I'd say it's probably worthwhile.