He relies on his physical attributes like Bailly. He's probably stronger and more wise at using his body than Bailly who can get caught out against stronger PL strikers. I wouldn't say he's all physicality though, you have to be switched on tactically and technically to play for Barcelona, which he has shown.
He's definitely the best CB of the next generation now that Boateng, Ramos, Godin, Hummels are getting older/struggling with form or injuries. Him, Gimenez and Koulibaly should be our main targets, all probably unattainable unfortunately.