The way apple talks about SIP its like a miracle we survived at all pre SIP. Pretty sure I've had SIP disabled for years now when I got nagged for something or whatever and had to disable it.
For tech-aware people, it is probably not necessary indeed. However, given that now “tech-aware” people are running completely random and unvalidated scripts w/o second thoughts (or even first thoughts actually) on their main machine, I’d say the “tech-aware” line is very very high…