These 3 posts I think mostly sum the situation up.
Beto's stock will be quite high now.
Hes a player who needs the ball ahead of him
He could net a lot of goals over a full season.
If we've budgeted £30mil for a CF and selling him would add £30mil to that budget -- if we could sign an 'elite' £60mil CF then should we? After all, we could keep Beto and use that £30mil for a top player in another position.
One thing to mention, if we looked at him being 1st or 2nd choice then hes got 2 years left on his deal. Extending his contract spreads out the payments further for PSR.