I've heard too many stories of folks experiencing a accidental discharge when decocking manually.
There have also been instances of accidental discharge when carrying Cocked and Locked, when the Safety Lever gets accidentally bumped to the OFF position.
With Firearms Handling in General, you can never be too careful.
I know manually decocking is an essential skill to have. I use the thumb roll method when I need to decock. However, my pistols are kept unloaded with the mag out of the gun until I need them. I don't carry, but if I did, it would probably be one of my striker fired pistols such as my G17 or XDM.
Off topic: My old CZ52 had a decocker that would fail the pencil test, launching the pencil into the air. I was never very trusting of decockers after that. How likely are decockers on other pistols to fail?
Larry
PS: Well I sometimes carry, I typically carry a 44 Magnum revolver when hunting in areas I know to have bear.
PPS: I'm aware of firearm rule #1: "Always point in a safe direction."