I think it makes arguably as much if not more sense than the Kane transfer, at least at the prices speculated. €80m, is what £65-68m? for a 21 year old emerging and getting numbers in one of the top leagues. Even if he doesn't live up to it, moneyncan be recouped, or another player can be signed. If he does well, can either stay long term or be sold for a profit. Pretty much the profile the club have been going for.
Or, £150m+ on a 28 year old, who fair enough is proven in the league. But that is big money to spend on the next 4-5 years.
I still think the club will go for and get Kane. But it wouldnt be atypical of the club to go for something like this if they've got to a point with Kane where it is beyond what they are prepared to value him at.