I personally haven't done it either, but am considering a $5-10k loan just to try it out. The 6-8%~ isn't worth it for the custodial risk to me as well.
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.