I hear you. It’s good practice to secure your system if you are out and about, or doing a project where the scope allows it.
My view is if you are using a web browser that connects to the public internet you are running in an insecure environment.
I think both of these posts are missing what SIP actually does.
SIP is
not an extra level of protection against, say, browser exploits—if some web page has managed to inject code into Finder (eek!), it doesn't matter whether apps are
normally allowed to inject into Finder, because the evil web page has already bypassed all of that.
Defense in depth is a good concept, but only when each layer of protection is designed to distrust one another, in case one of those layers gets broken. SIP isn't really designed that way. SIP distrusts the
user of the machine and prevents
the user from performing certain actions.
And a lot of users
should be distrusted. How many casual Mac buyers understand the significance of entering their admin password? But if you know what SIP is, and how to turn it off, you probably aren't one of those people. There's no equivalent of SIP in most Linux distributions, and the closest equivalent in Windows is far more lenient (except with regard to drivers/kexts, Windows is a downright pain about those).
I really can't say I understand all the concern about SIP, and I frankly think there's an awful lot of FUD going around.