I was thinking about it for tax savings purposes (loan), but Bitcoin is getting so much valuable over time that it's not worth the custodial risk for me.
You need to pay 10% interest for loaning against 50% of your BTC.
Of course BTC's price probably won't go under $20k ever again, but in March when it went from $8k to $4k for half an hour, a lot of us were surprised.