With the player having a good season with great stats, with the fee relatively low I'm surprised nobody moved for him earlier on in the window.
You can see the sort of player Wenger has aimed for this summer, with the heavy links to Mahrez and Vary's clause being triggerd and now Lucas Perez it's safe to say Wenger wanted to add an attacking wide player, who can play as a striker and can score from either position.
With Ozil not being a goal threat and Giroud being limited, it's important for us to have other players scoring and allowing Ramsey to roam up and down at will isn't the safest way to play, so Sanchez on one wing and Perez on the other has the potential to do wonders.
Perez---Giroud---Sanchez
----------Ozil--------
