Agree with the broad idea. I'm sure Pep would have preferred to have him out on loan for another year or two.
It's a difficult balancing act. I remember watching Trippier, who is now Spurs first choice right back, win the FA youth cup for City. How great would it be to have him now?
But it's taken him years to peak and he's only got so good by learning/earning his position by playing hundreds of games for Burnley in The Championship, then the Premier League, then moving to Spurs and improving further.
It's difficult if not impossible to recreate that process through loans. At the same time the standard is so high at the top end of the league that you can't always afford to indulge a young player, who will need to learn from his mistakes.
Looks like things have fallen right for Maffeo; it's a big chance for him.