I can't seem to wrap my mind around it, why is POS untrustworthy and POW trustworthy? So I have to trust a miner who has millions and millions of hashing power that he will not generate dozens of blocks in a series? That happens now, everyday and no one seems to care.
You can generate PoS blocks without even trying and as it is now, they can "overwrite history", which is bad.
For PoW, however, you must spend a lot of electricity so it actually costs you something (quite a lot) trying to change history.