Put another way, you’re saying macOS’s admin account is currently too powerful? Even if Apple is able to eventually change that—and it would take a while—it doesn’t make SIP useful for security as of right now.
Edit: Also, security be damned, I don’t want to use an OS without a proper root account! So while not entirely relevent to the discussion, I know that I would either continue to turn off SIP or move to another platform.