Securelevels useless?

Securelevels useless?: "Several people wrote in about Jason Miller's article
How not to respond to a security advisory
in a SecurityFocus opinion column. The short version is that a
recent advisory shows that root can temporarily replace system immutable files (see
chflags(1)) by mounting over them.
That's not a shockingly new discovery (some people would even expect that to be the case), but Jason took offense in Theo's
vendor reply, which reportedly was 'Sorry, we are going to change nothing. Securelevels are useless.'.

Taking that statement literally, Jason concludes that OpenBSD should completely remove its
securelevel(7) implementation.

One obvious different interpretation would be that system immutable guarantees what the man page says, namely 'An immutable file may not be changed, moved, or deleted.', and not that it guarantees any read access will result in approved data. And there are other uses for securelevels besides chflags, and they need not all be equally useless. Or are they?

"