The caution to leave an empty chamber under the hammer applies only to the old Colt Single Action Army design and clones, and other similar actions such as the early model Rugers, etc. It DOES NOT apply to double action revolvers, such as the S&W's, Colts, Tauruses, etc.

The reason for this procedure with the old-style single actions is that the safety notch on the hammer can be sheared by any significant blow on the hammer spur, allowing the firing pin to hit the primer & fire the piece.

Many of the old-time gunslingers used to carry a $5.00 bill in the empty chamber to pay the undertaker in case they got killed......

IF you can handle the recoil and do good shooting with the .357 (which is just a souped-up .38 Special), the .357 is generally regarded as a superior cartridge for hunting and self-defense. But it depends on how well you can shoot that round. Some people get a .357, and use .38 Special ammo in it for target shooting, practice & plinking. They then load it with .357 cartridges for "social" purposes.....