yes impose a collateral on tBTC implies they have certain values while they should not...
We all understand that. mocacinno already answered someone about this concern and I personally agree with him.
I know some have criticized me for asking collateral, but if i'd lend out tBTC to newbies without asking any collateral, i'd end up with an empty tBTC wallet and i could just shut down my faucet altogether. tBTC is worthless, but that doesn't mean it's free to mine, so if i loan out tBTC and you default, i need some real BTC to mine tBTC to replenish my faucet's wallet...