You recommend going against the advice of an authorized Apple/Mac service center? Ok, I guess that's your opinion.
Now we will let you answer the real world IT questions here...
How do I know if my family or employees will Practice Safe Computing? Despite telling them over and over not to do it... We have various employees for years that always tried to and actually did install programs/apps on our business computers. Some of the business computers are a remote location that we don't access every day. Our PCs running Windows were unusable much of the time and I had to waste time (an unbelievable amount of hours every year) traveling to those locations to get infected computers up and running again.
We used AV software that helped with the Windows machines but sometimes they would even bi-pass the protection warnings to install their software. Switching to Macs helped for the last five years but we still have found unauthorized applications on them that newer employees installed (games, phone apps, etc..) even though we clearly told them not to when they were hired. (Yes this all really happened).
Note: I have Mac Security software installed on ALL the work computers and it has worked well... never caused a single problem... I actually just spoke to one our employees... a manager... this past week at a remote location... several hours travel away from me and I made sure the MacOS (10.14.x) and the Mac Security software was fully up to date... but
since you have been arguing for a few weeks about how we don't need it I figured I would ask if you have another solution.
Also,
our local computers... Windows PCs and Macs that have family and employees using them also are kept fully updated with Mac Security software and they too have been completely trouble free from infections (all of them trouble free including Windows PCs).... but I do get calls on the phone several times a year about what to do when the security software pops up with a Warning about a bad link or an infected file being blocked... (the Mac security software blocks the infections usually before the Windows VM security software does).
They have been told the Safe Computing Principles just like you listed but they forget and still open attached files.... some of the attached files need to be opened that come from our vendors, associates and from those remote locations.... the ones that I don't have access to and from the computers... Macs and PCs... and Macs that you suggest DON'T need security software.
I've spent more time arguing with you and others on this topic (hours and days) than time I spent dealing with any infection related problems on our all business and personal computers for five years. Since you have been arguing with me for at least this past week over this
I figured I would give you a chance at explaining your solution... despite the fact that using the security software on ALL the machines has kept everyone working trouble free with very little time and effort by me.