Angular2: Why to use private access specifier to instantiate the providers in constructor

Question

Why to use private access specifier only to instantiate the providers in constructor ? Is there any specific reason to use private access specifiers only ?

Private injection

constructor(private service: InjectedService)

Public injection

constructor(service: InjectedService)

Answer 1

Using private acts a shorthand, instead of doing:

constructor(service: InjectedService) {
   this.service = service
}

you can:

constructor(private service: InjectedService) {}