Let me explain, for example you have 1 btc in your account and you want to sell it but bitcoin price is very low 8.5k USD now. If you sell your 1 btc at this rate that's fine instead of 60% you got 100%, but if after few days btc price goes upto 25k USD then you will regret cause price increased by 300%. If you want your 1 BTC back you will have to spend 25k USD + Fee now.

If you take a loan from them, you will get 5.1k USD from them instead of 8.5k USD, but if bitcoin price get to 25k USD you can still give them 5.1k+Interest and get you btc back.


And about Trusting them, I noticed a topic in stake forum by Edward (Owner of Primedice & Stake), He recommended their service in that topic. As, primedice and stake both are running with very good reputation in market for a very long time, i think it have some value. Here is the link: https://forum.stake.com/topic/6754-large-loans-available-collateral-needed/