They also invented what i call the shadowcrap-dilemma:

1) To make a PoS Network "secure" you need to have nearly all wallets staking.
2) To make Ringsignatures "secure" you need all people to use them, always.
3) But you can't stake the tokens they use for anonymity, so being private and having a secured pos network can never be happen at the same time.

This is a typical example of getting fucked by your own greed.