Re #1, I think the advantage of KeyChain is compared to single site posting key log-in is marginal, but compared to using a TTP solution like SteemConnect is massive, and Steemit Inc leading the way in implementing it is promising with respect to the potential of doing away with TTPs in the STEEM eco system all together.

It's a first step. An important first step towards a SteemConnect/SteemLogin)TTP free DApp eco system, and a first glimmer of hope after the public support for EIP that Steemit Inc hasn't completely lost all sense of direction.