lets see:

Save bandwidth

daemon would pull updates every x mins and cache

multiple clients would pull from the daemon

Daemon could have simpler auth mechanism then the API

Saving mor bandwidth

reducing the number of Auth'd clients on the Pump server

- especially since pump servers still lack a way to de-auth clients

Daemon could serve from cache and cache posts while pump server was down

Daemon could make it simple to have all clients connect Via Tor istead of having to set each client up fo do so manually

and more that I can't think of right now