Like Politano, I think this will go down a very smart, shrewd signing (although for different reasons)
First, it allows us to offload Eder, who's not completely useless but doesn't have much upside and will NEVER challenge Icardi for a starting spot.
Second, it puts a LOT of pressure on Icardi. We have until the 15th to see if a P$G or RM comes along with 110 mil to buy him (which they won't), and now Icardi will have to prove he is worth a new contract, with Lautaro breathing down his neck.
Oh, Icardi's not performing, or missing sitters? Bench him and start LM. Harsh, but we had nobody we could do that with last year.
The kid also seems flexible and able to play multiple positions. Playing style is remniscient of Aguro/Tevez, second striker or strike. May be able to play as an outside forward, RF kind of position (probably not as an out and out winger, but why not? If there's injuries, start him a game, who cares? He's young and fast, let him explore his strengths and weaknesses).
Particularly with versatile players like Asamoah (LM, LWB, LB, CM), Perisic, Skriniar (can play DM), DDA (anywhere across back-line), potentially Florenzi (RB, RWB, RM, CM), we can probably switch from 3-5-2 to 4-3-3, 4-2-3-1, or even 4-3-2-1 Christmas tree mid-game and it seems like he may have a position in all of them. This is very valuable, particularly with a solid, tactical coach like Spaletti.
The price seems good for what we got him for, considering BVB bid way higher than we did but it was already a done deal. Considering their player evaluations and development the last few years, they probably think he's a stud which is a good thing (thanks Milito).
All in all, seems like a good signing. Won't have pressure to perform as he won't be a starter but there will be time for him to play (as long as Spal trusts him somewhat), looks versatile, good price, may be super valuable if he performs (esp in Champion's League), and finally puts pressure on Icardi to perform every game.
Would love to see him and Icardi be an awesome 1-2 punch striker combination for years to come both at Inter, and hopefully the National Team.
Can you imagine the next World Cup, if Argentina can string some good defenders and midfielders, having them play a 4-3-1-2 with Messi in the hole and LM and MI9 up top?! Would be deadly!!