River doesnt appear until the eighth episode of Series Four, so recommending Doctor Who for the River Song episodes is like recommending Lost for the Desmond episodes
Similar to Big Score, effects like Deadly Dispute only count as card advantage if the Treasure is enough of a bonus, since you're otherwise exchanging a creature and a spell for two different cards (a 2-for-2 exchange)
Using her in this format allows her to partner with a Background, giving your Commander deck a unique flavor that opens a larger card pool for you to play with
I can't recall a cycle of cards in a new expansion that did a bunch of great things like these and then add in the keyword to them as well as these, which is pretty common now
Importantly, though, the value of the Elven Council deck mostly lies with a few key cards, which might be easy to sell individually
MTG Commander Masters Deck - Silver Swarm for Magic the Gathering