modern consensus is that a manual safety is more of a liability than a feature - correct handling obviates it, and in the worst case a manual safety may prevent you from deliberately firing the weapon.

correct handling requires the use of a holster which completely covers the trigger. a properly-designed firearm is safe in a properly-designed holster.

the handgun that effectively established this concept (the glock) does not contain enough potential in the fire control at rest to discharge a round, but notably, the p320 does.