Earlier quoted context omitted.
which you only have to worry about when you have to tap into the rainy day fund, or when the collateral gets liquidated Because you can borrow against it instead of selling and without touching a financial institution, and this gives you liquidity without a tax event Welcome to the 2020s
"which you only have to worry about when you have to tap into the rainy day fund, or when the collateral gets liquidated" If your 'rainy day fund' is a stack of bills in a box, sure, but other than that there isn't much you can do with significant amounts of money that isn't going to involve some kind of transparency. Literally trading those dollars for anything else involves gain/loss. You're not going to be able to…
there is no obligation to report possible deductions.
you wouldn't here and you would remain compliant if you paid the interest with money you already paid taxes on.
the rest of your analogy just doesn't work.