everyone lends with 120% altcoins collateralls but do not sell altcoins and buy btc ?why would he ask for loan if they on altcoins when on bittrex you can buy btc with some altcoins easy
explain somebody the purpose of this loan ?
Because the people who use altcoins as collateral believe that their collateral-altcoins are undervalued at the time they get a loan. For example, you use Doge as collateral and the value is about 24 satoshi each, but you think it will go up by x5 in the next weeks. That is the reason. Also most of the people who use altcoins as collateral buy more altcoins using the loan.