Earlier quoted context omitted.
Low certification levels certify low levels of security. High certification levels certify high levels of security. EAL4 is known to be too low against modern threats that will attack commercial users. We know this from experience where EAL4 systems are routinely defeated. Higher certification levels, such as the SKPP at EAL6/7, are known to be able to resist against much harder threats such as state actors like the…
> Low certification levels certify low levels of security. High certification levels certify high levels of security. I guess I don't know enough to say but I just doubt that, knowing what I know about other certifications. I expect that they're perhaps lightly correlated with security.
For example, a squat test is a reasonable measure of leg strength. Only squatting 20 kg means your leg strength is extremely weak. The test procedure is fine, getting results like that is not. If that is all you can do, that is quite problematic.
As to the certification itself, it is pretty good. Easily hacked products like iOS, Linux, and Windows are consistently unable to certify as moderately secure. That is vastly different than basically every other certification where products like Windows pass with flying colors even though we all know that is nonsense.
So, at the very least, low certification levels like EAL4 provide high confidence of lackluster security. You can withhold judgement of high assurance levels corresponding to high security if you like, but low assurance levels corresponding to low security is pretty clearly established.