The fact that holders of a coin "value" it in an affectionate sense is no substitute for such an economic role. There are plenty of POS coins out there that can substitute for Blackcoin. So at the moment I'm thinking that this coin's value is based on the multipool effect and some strong promotion. I'm not saying thats bad, I'm just saying it's *it*.
I couldn't find any decent PoS substitutes for BlackCoin.
Peercoin - Don't like fixed 0.01 fee.
NXT - Don't like fixed 1.0 fee.
Faircoin and Mintcoin - You are penalized for sending and receiving coins as your coins have to be in your wallet for 21 days before you accumulate interest. MNT - Lose 20% the first year. FAC - Lose 6% the first year.
Why can't there just be a normal PoS coin? There is one right now. It's Blackcoin.
Low reward POS coins suffer the same than low reward POW, are less resilient to an attack.
So FairCoin and Mint have something in favour. interes also make people hold LONGER, and this is desirable.