IPhone 17 is around $1700 to one device, those that mean I can keep $1600 on my iPhone and feel safe? This analogy doesn't make too much sense. I think if we are having funds that we are not going to move from one wallet to another often like deposit to exchange and withdraw, it's better the money remain idle on offline wallet until the coin is ready to be spent.
I second your opinion. If the money isn't going to be spent, it's best to just store it on a wallet that you're not going to use often. Hardware wallet is what the majority will say about this or an airgapped wallet which suits it. I don't practice this because I've got my funds stored on a wallet that I only access a few times when I have to, like when it's time to dump and sell.