Even in those cases, I'd still just use the savings directly. I have and it's been fine, I don't regret it.
Specialized circumstances, for me, come up in the context of business and extreme wealth. W...
Most folks really don't need one, agreed. One quiet case for individuals though: a surprise expense or big purchase where selling would trigger a taxable event. Borrowing against the BTC sidesteps that. Not a safety blanket, just tax math.