[rocqua]

It seems that PoW does not need phone a friend to compare "which of these two chains is the true one", whilst PoS does need phone a friend for that.

However, that presumes all forks are soft forks; that you are presented a correct chain; that you want the soft fork with consensus rules accepted by most miners. (If verifying with an old bitcoin client the BCH BCT split will be resolved for you without you having a say.

In summary, PoW has less need for Phone a Friend than PoS. But it still has some problems.