Bitcoin or crypto-backed loans are nothing new. They're offered by both crypto and traditional financial companies. Even in this forum, it's available. A crypto-backed mortgage is just another kind of crypto-backed loan.
But why do you think it's a smart move to use your Bitcoin or crypto as a collateral when the market is down? Although, yeah, it helps you avoid getting liquidated, it also means you're getting a much lower value of what you have. You're risking your Bitcoin to a third-party in exchange for, say, 40% or 50% or 60% of its value. Personally, I don't think it's worth it.
Maybe he didn't see what's going around on Lending section
https://bitcointalk.org/index.php?board=65.0That's why he made that conclusion and got amazed on that possibilities. These situation is not new and for many years this crypto backed mortgage is running in crypto space.
I also don't know why they like the idea of using their Bitcoin and it make them looks desperate to get quick funds. They might just waste some opportunity to get good profits with their Bitcoin especially if they use it for collateral matters or other unwanted things.