Well here in the US when NOT is in all caps like it means it's wrong.
I doubt that very much. Capitalizing words is making the statement stronger, it does not change the meaning of something. Seems rather an personal interpretation than a real thing.
What you choose is your own responsibility ofcourse.
And you might consider it safe, but that does not mean that it generally is, maybe for you, bot not for most people. For most it's not. And even you can make a typo or maybe leave a space by accident.
Changing 4 files is 4 times an option for an error. And a system command rarely has issues compared to manual entry's.
If I use userdel I don't know what the command is doing unless I research it.
Userdel is basic linux knowledge. Needs research 1 command. What you are doing one needs to know what all those seperate files do.
So that is not an argument.
I also still change custombuild manually, but that is a .conf file meaning a configuration file, not a system file.
As for the last alinea.... in any system anything can go wrong. Not booting can be just as riskfull as booting, but I don't consider anything of that kind safe but rather "kind of safe". Same with updates of any kind. We've also seen enough DA updates with issues.