Inter winning the UEFA Champions League would make Serie A much stronger, and bring more exposure towards the league. PSG will also break a long-standing spell of not having at least one of the Champions League trophy.
Serie A actually come back in recent seasons even their clubs no longer have too good finance compare to clubs from Premier League, La Liga and PSG from Ligue 1. They have a smart approach by combining their old players, young players and players from loan contracts. This way, many clubs in Serie A don't have to pay a lot of money for player transfers and salary while they can manage to build up their squad well especially from young players. They still have problems of maintaining their squad quality with replacement of old players and loaned players but generally they are doing just fine.
I'm rooting for PSG but I can say both teams deserves it, their efforts has been commendable and it means a lot to both teams. Both has experienced defeat in the UCL finals within the last five seasons of the UCL.
Both teams are same in quality and ambition of winning Champions League trophy and personally it's really hard to pick a winner and also champion. In a big match between two teams with many star players like this, a match result can be decided by one moment or within several minutes. PSG or Inter Milan can be stronger than their opponent a little bit but it does not result in any guarantee of a trophy.
I guess in the next five seasons, one of them will make it to another final again and that maybe PSG or both.
PSG have more chances of joining Champions League final match in next seasons than Inter Milan by having better and deeper budget for their club developments. Inter Milan but they have many players who will soon go to downside of their career in next seasons that potentially affect performances of Inter Milan in general. Another disadvantage of Inter Milan is their finnace that is not abundant like PSG and it can prevent them replace old players with young players well enough.