#1 Lampard knows the club inside out
Frank Lampard has played alongside a few players who are currently in Chelsea, a few being Willian and Cesar Azpilicueta, which only means that the former midfielder knows the strengths and weaknesses of the players, and how they would react to varied situations.
In addition to the same, Mason Mount, who has been recalled by Chelsea from Derby County, played under Frank Lampard last season.
Besides, Lampard has been at the club for majority of his career which spans almost 13 years, implying he knows the club's philosophies and operations inside out, which in turn leads to the fact that he might not require a lot of background check on the club.
He has shepherded Chelsea to unimaginable heights over the years, and now the fans will be extremely excited to see him in the dug out, marshaling the players and aiming to bring the best out of this football club.