To me POS coins have no reason of existance.
You could say that they're saving energy but in order for the stake to be useful you need a fair distribution.
In order to achieve a fair distribution most POS coins are minable as well. How is that saving energy? More recently a trend to POS coins is that they are 100% POS with "fair distribution". Is this an actualy fair distribution? I don't think so. A limited amount of people get to have access to the coins. Everyone else will have to buy them from them. This is the exact oposite of bitcoin's mining idea inspired by real world gold mining.
TL;DR imho 100% POS coins have no furure.