Question is how much he trusts his abilities and what type of effect he thinks he can have at Barca. Remember we play at Montjuic next season. Won't be the same feeling.
There are two scenarios for him to consider:
1. He's good enough to elevate the team, to win trophies to add to his tally and help us get further in Europe. He'll get recognition from the fans and satisfaction like the pre PSG days he's been missing since leaving (apart from Argentina). Won't carry us like the old days but will certainly be a big help. The good ending.
2. He's going to need a lot of help from his teammates. Signing him will be like signing Raphinha. He'll have ups and downs, will be criticized for not perfoming well enough. We won't be competitive for trophies and the return will be negative for all parts including the last memory we'll have of him. A sad end to the story.