The security of these certificates only guarantees that you’re talking to the right server and that your communication is encrypted. For other concerns like of the server was hacked, you’ll need something else. No individual piece of security tech can secure everything. You as the site admin can only use it as one piece of a comprehensive security package that defends against what you perceive as the most credible threats.
Asking where’s the security is like asking where’s the protection with a bullet proof vest if you can still get shot in the head. A vest offers one type of protection, but a comprehensive security package is going to include other pieces like helmets.
Man, you’re giving me flashbacks to real analysis. Shit is weird. Like the set of all integers is the same size as the set of all positive integers. The set of all fractions, including whole numbers, aka integers, is the same size as the set of all integers. The set of all real numbers (all numbers including factions and irrational numbers like pi) is the same size as the set of all real numbers between 0 and 1. The proofs make perfect sense, but the conclusions are maddening.