#3 His footballing prime is ahead of him.
A player's age is an extremely important factor to consider when buying a new player. Extremely young players take some time to fit into a squad while ageing players lack the longevity that clubs look for while signing a long-term prospect.
With that being said, Jorginho just turned 26 last year. He's not too young nor too old. He's just entered his footballing prime.
A footballer hits his prime between the age of 26-29. By signing him at this age, Chelsea have got themselves a mature footballer who's ready to fulfill all his potential.
Jorginho easily has a good four years of football ahead of him. Four years of prime football. In that respect, paying £57 million was not such a bad idea after all.
His maturity is bound to help Chelsea in the long-run.