Proper firearm practices don't protect you from deliberate self-harm, nor does it protect the other people living in the space from a resident motivated to do them harm. Following proper safe firearm practices protects you and your family from negligent discharge and from someone turning your firearms against you. But it does absolutely nothing to protect you from yourself, nor protect your friends/family from you. You know who doesn't shoot their friends/family/self whilst in the grip of a severe, acute mental health episode? A person who doesn't have easy access to guns.
About 42% of adults in the US live in a household with guns[0]. If your claim is that the statistics [that show living in a household with guns is more dangerous than not] are easily mitigated via good practices, then a HUGE number of people must not be following those practices. Why else would the statistics be so clear on that point? Either a large proportion of people are not following those practices, in which case some other mitigation is necessary, or those practices are not as effective as you claim, in which case some other mitigation is necessary.
I bring this up because my wife and I have discussed at length whether or not to conveniently locate our firearms for self-defense, and concluded that, for now at least, adequately keeping our kids safe from using the guns without supervision basically precludes using the firearm for self-defense (that old "when seconds count..." saw), to the extent that we don't keep our firearms in our home.
0. https://www.pewresearch.org/short-reads/2023/09/13/key-facts...