For me, if we've had to pay an extra few million for him and that leads to other top players considering us to be a credible choice the that's money well spent.
Not for a second am I comparing this stage to what happened at Man City, but there are some parallels as there have been with other clubs (Bergkamp to Arsenal for example) where there's a tipping point in how you're viewed, by the media, top level players etc. People are taking notice now. The smirks are fading.
With the payments to PSG etc, it seems to me Monchi has had his work cut out for him with this deal and played an absolute blinder. What signings he and Emery have been.