It all depends on your definition of "secure". - What kind of attack do we need to prevent? - What do we need to be protected from? - What do we not need to

It all depends on your definition of "secure". - What kind of attack do we need to prevent? - What do we need to be protected from? - What do we not need to be protected from? All of this (and more) must be defined in your threat model. A threat model precisely defines what "security" means for you in your context. Without that the concept of "security" remains extremely vague and therefore it can always be called imperfect against an incredibly intrusive attack