How often does human error cause issues? Recently we had a rocket crash in Russia,there have been numerous incidents of drone crashes as more and more unmanned aircraft take to the skies, and a few years ago we had an Air France disaster that might have been cause by humans making poor decisions or engaging the wrong controls. Those are incidents where the wrong button press has large consequences, either in physical damage or the loss of life.
Many of us make mistakes constantly as we work in the various tools and environments we need throughout our day. We click the wrong button in SSMS, we connect to the wrong server and run a script, or we fail to test a change. All of these are mistakes made by humans, and often are mistakes that can be prevented if we did a better job or sticking to routines and processes. That can be hard, but perhaps checklists can help here, along with some double checks by coworkers.
That's why I think using scripts in T-SQL, and using the Script button in SSMS to generate the code that you can run (and save) is the best way to work with your servers. As much as I think Powershell (PoSh) can be a pain to write and debug, there's a good argument to be made for using it when performing complex administrative tasks, especially across servers. Using code rather than forms and buttons is just a better way to accurately and consistently make changes in a controller manner.
This is an area where everyone could work more efficiently. Developers are usually used to working with version control systems and tracking all their changes. However they often will make configuration changes to their machines, SQL Server, IIS, or some other software, and forget to track the changes. Making these changes in code, through T-SQL or PoSh, and tracking these items in VCS, would help with smoothing software deployments. DBAs and other operations staff should learn to use version control systems as well, helping to track down root causes to issues.
Ultimately humans are often the weaknesses in most systems. We should understand that, accept it, and compensate as best we can.